Bio

Clinical Focus


  • Anatomic Pathology

Academic Appointments


  • Assistant Professor - Med Center Line, Pathology

Professional Education


  • Fellowship, Brigham and Women's Hospital, Women's and Perinatal Pathology (2014)
  • Residency:Brigham and Women's Hospital (2013) MA
  • Board Certification: Anatomic Pathology, American Board of Pathology (2013)
  • Medical Education:Stanford University School of Medicine Registrar (2010) CA

Publications

All Publications


  • Evidence for lineage continuity between early serous proliferations (ESPs) in the Fallopian tube and disseminated high-grade serous carcinomas JOURNAL OF PATHOLOGY Soong, T., Howitt, B. E., Miron, A., Horowitz, N. S., Campbell, F., Feltmate, C. M., Muto, M. G., Berkowitz, R. S., Nucci, M. R., Xian, W., Crum, C. P. 2018; 246 (3): 344–51

    Abstract

    The distal Fallopian tube is a site of origin for many 'ovarian' high-grade serous carcinomas (HGSCs) with intraepithelial carcinomas (STICs) that share identical TP53 mutations with metastatic tumors. TP53 mutation-positive early serous proliferations (ESPs) comprise a spectrum including p53 signatures and serous tubal intraepithelial lesions (STILs) and are not considered malignant; however, ESPs are often the only abnormality found in Fallopian tubes of women with metastatic HGSC. The purpose of this study was to determine if a relationship exists between isolated ESPs and concurrent metastatic HGSCs in the absence of STIC. Fallopian tubes from 32 HGSCs without a co-existing STIC/HGSC in the endosalpinx were exhaustively sectioned. The presence of either STIC/HGSC or ESP in the endosalpinx was documented and DNA from tissues containing ESPs, concurrent HGSC, and control epithelia were interrogated for TP53 mutations by targeted amplicon-based sequencing with average coverage reads >4000 across DNA replicate samples. Serial sectioning revealed a previously unrecognized STIC/HGSC in 3 of 32 (9.3%) and ESPs in 13 (40.6%). Twelve contained TP53 mutations. Nine (75%) shared identical TP53 mutations with concurrent HGSCs, four at high (≥ 5%) and five at low (< 5%) allele frequency. All control epithelia were TP53 mutation-negative. This study, for the first time, indicates lineage identity between ESPs in the distal tube and some metastatic HGSCs via a shared site-specific TP53 mutation. It supports a novel serous carcinogenic sequence in which an ESP could eventually culminate in a metastatic serous cancer via 'precursor escape' and would explain the apparent sudden onset of cancers without co-existing STICs. This paradigm for serous cancer development underscores the likelihood that multiple precursor types in the Fallopian tube contribute to serous cancer development with implications for the evolution, pathologic classification, and prevention of this lethal malignancy. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

    View details for DOI 10.1002/path.5145

    View details for Web of Science ID 000447161600010

    View details for PubMedID 30043522

  • Clinicopathologic and Immunohistochemical features of uterine Adenomyomatous polyps. Human pathology Strickland, K. C., Yuan, L., Quade, B. J., Nucci, M. R., Howitt, B. E. 2018

    Abstract

    Adenomyomatous polyps (APs) of the uterus (also termed polypoid adenomyomas and pedunculated adenomyomas) are exophytic proliferations composed of myomatous stroma admixed with endometrial glands. APs can be diagnostically challenging, mimicking polypoid neoplasms such as atypical polypoid adenomyoma and adenosarcoma. The purpose of this study was to describe the clinicopathologic, morphologic, and molecular features of APs, as well as to raise awareness of this entity as a potential source of diagnostic confusion. We identified APs diagnosed at Brigham and Women's Hospital from 2000 to 2015. We reviewed histologic slides and obtained archival tissue for immunohistochemical and molecular studies. APs seen in consultation were associated with a broad differential, including adenosarcoma, atypical polypoid adenomyoma, and endometrial neoplasia. We performed a histologic review of 84 APs diagnosed at our institution and identified two distinct morphologic types of APs, which we have termed type 1 (with vaguely fascicular myomatous stroma intimately admixed with glands) and type 2 (containing a well-defined stalk of smooth muscle entrapping glands). The majority of APs exhibited CD10 (100%, 72/72) and desmin (97%, 70/72) positive stroma. Diffuse caldesmon positivity was present in 97% (28/29) type 2 polyps, compared to 8% (3/39) of type 1 APs. APs did not harbor mutations in exon 2 of MED12. APs are not uncommon in routine practice and may be misinterpreted as more worrisome lesions. We identified two types of APs with distinct morphology and immunophenotype. The absence of MED12 exon 2 mutations suggests that the pathogenesis of APs is separate from uterine leiomyomas.

    View details for DOI 10.1016/j.humpath.2018.10.002

    View details for PubMedID 30339971

  • HPV 6-associated HSIL/Squamous Carcinoma in the Anogenital Tract. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Liu, M. Z., Hung, Y. P., Huang, E. C., Howitt, B. E., Nucci, M. R., Crum, C. P. 2018

    Abstract

    Human papillomavirus (HPV) type 6 is historically classified as low-risk HPV type and associates with low-grade squamous intraepithelial lesions of the anogenital tract. Rare squamous carcinomas have been reported in association with these HPV types but the mechanism(s) behind this carcinogenic sequence have been unclear. We report 4 cases of low risk anogenital HPV infections-3 cervical (immature low-grade squamous intraepithelial lesion with metaplastic phenotype) and one anal (exophytic condyloma) lesion-that manifested with high-grade squamous intraepithelial lesion/squamous cell carcinoma. Two were associated with invasion one of which metastasized to a regional node. Two cases exhibited strong p53 positivity in the high-grade squamous intraepithelial lesion/squamous cell carcinoma component analogous to that seen in HPV-negative differentiated intraepithelial lesions of the external genitalia. This series of cases adds to the literature on low risk HPV-associated cervical squamous carcinomas. It underscores the similarities between the baseline cyto-morphology and benign mimics (low-grade squamous intraepithelial lesions), the subtle cytologic and immunohistochemical (MIB1) features heralding biologic aggressiveness, and in some potential pathways (p53) not usually involved in HPV-related anogenital neoplasia.

    View details for DOI 10.1097/PGP.0000000000000556

    View details for PubMedID 30312218

  • SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus): a clinicopathologic entity distinct from undifferentiated carcinoma MODERN PATHOLOGY Kolin, D. L., Dong, F., Baltay, M., Lindeman, N., MacConaill, L., Nucci, M. R., Crum, C. P., Howitt, B. E. 2018; 31 (9): 1442–56

    Abstract

    Small cell carcinoma of the ovary, hypercalcemic type is a rare, aggressive malignancy which usually occurs in young women and is characterized by mutations in SMARCA4, with few other alterations. We recently encountered uterine tumors with morphologic, immunohistochemical, and genetic similarities to small cell carcinoma of the ovary, hypercalcemic type. Herein we report the clinicopathologic and molecular features (using a targeted massively parallel sequencing [MPS] assay) of these tumors. The cases were diagnosed on cervical and endometrial biopsies (n = 2, 34, and 29 years) or hysterectomy and bilateral salpingo-oophorectomy (n = 3, 25, 33, and 58 years). The tumors were composed of sheets of large atypical epithelioid cells with prominent rhabdoid morphology, indistinguishable from the "large cell" variant of small cell carcinoma of the ovary, hypercalcemic type. In three cases, the ovaries were pathologically examined to exclude a primary ovarian malignancy. Immunohistochemically, four of four cases showed SMARCA4 loss, and were negative or only focally positive for keratins, EMA, and claudin-4. One of three cases was positive for WT-1. Targeted MPS was successfully performed on 4 of 5 tumors, and showed recurrent mutations in SMARCA4, with few other alterations. Of the cases diagnosed on hysterectomy, all had extensive lymphovascular invasion, extra-uterine spread, and marked infiltrative growth. These tumors were uniformly aggressive; all patients died of disease (median survival 7 months, range 1-43 months). We propose this entity be called "SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus)", a term which describes both the tumor's underlying molecular abnormality and its morphology. Its unique clinicopathologic and molecular features differentiate it from other related malignancies, including undifferentiated endometrial carcinoma, small cell carcinoma of the ovary (hypercalcemic type), and epithelioid sarcoma. We review and discuss previously reported "rhabdoid tumors of the uterus;" while they are a heterogenous group of tumors, some of them are likely examples of this entity. Correctly identifying cases of SMARCA4-deficient uterine sarcoma from histologic mimics is important as it may have prognostic, predictive, and germline implications.

    View details for DOI 10.1038/s41379-018-0049-z

    View details for Web of Science ID 000444569400010

    View details for PubMedID 29700418

  • Inter-pathologist and pathology report agreement for ovarian tumor characteristics in the Nurses' Health Studies GYNECOLOGIC ONCOLOGY Barnard, M. E., Pyden, A., Rice, M. S., Linares, M., Tworoger, S. S., Howitt, B. E., Meserve, E. E., Hecht, J. L. 2018; 150 (3): 521–26

    Abstract

    Grade and histotype of ovarian carcinomas are often used as surrogates of molecular subtypes. We examined factors affecting pathologists' reproducibility in two prospective studies.Two pathologists independently reviewed slides from 459 incident ovarian cancers in the Nurses' Health Study (NHS) and NHSII. We described agreement on tumor characteristics using percent agreement and Cohen's standard kappa (κ) coefficients. We used logistic regression, with disagreement as the outcome, to evaluate the contribution of case and tumor characteristics to agreement.Inter-rater agreement was 95% (κ = 0.81) for carcinoma versus borderline, 89% (κ = 0.58) for grade and 85% (κ = 0.71) for histotype. Inter-rater grading disagreement was higher for non-serous histotypes (OR = 4.66, 95% CI 2.09-10.36) and lower for cancers with bizarre atypia (OR = 0.13, 95% CI 0.04-0.38). Agreement with original pathology reports was 94% (κ = 0.73) for carcinoma versus borderline, 78% (κ = 0.60) for histotype, and 79% (κ = 0.24) for grade. Grading disagreement was significantly lower for tumors with 'solid, pseudoendometrioid or transitional' (SET) architecture (OR = 0.08, 95%CI 0.01-0.84). Date of original diagnosis, hospital type, number of slides available for review, tumor stage, and slide quality were not related to agreement.Overall, inter-rater agreement for tumor type and grade for archival tissue specimens was good. Agreement between the consensus review and original pathology reports was lower. Factors contributing to grading disagreement included non-serous histotype, absence of bizarre atypia, and absence of SET architecture.

    View details for DOI 10.1016/j.ygyno.2018.07.003

    View details for Web of Science ID 000444528400020

    View details for PubMedID 30001835

    View details for PubMedCentralID PMC6102072

  • Targeted Genomic Profiling of Female Adnexal Tumors of Probable Wolffian Origin (FATWO). International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Mirkovic, J., Dong, F., Sholl, L. M., Garcia, E., Lindeman, N., MacConaill, L., Crum, C. P., Nucci, M. R., McCluggage, W. G., Howitt, B. E. 2018

    Abstract

    Female adnexal tumor of probable Wolffian origin (FATWO) is a rare gynecologic neoplasm of low-malignant potential presumed to be derived from mesonephric remnants in the upper female genital tract. Similarly, mesonephric remnants in the lower female genital tract are thought to be the origin for mesonephric carcinoma. Although the molecular alterations in mesonephric carcinoma have been recently reported, the pathogenesis of and molecular alterations in FATWO are not well understood. The aims of this study were to examine the molecular alterations in FATWO and to establish whether these neoplasms are molecularly similar to mesonephric carcinoma. Eight FATWOs underwent massively parallel sequencing to detect single nucleotide variations, copy number variations, and structural variants by surveying exonic DNA sequences of 300 cancer genes and 113 introns across 35 genes. Good quality DNA was isolated from 7 of 8 cases. Novel KMT2D variants (1 frameshift, 3 missense) were identified in 4 of 7 cases (57%), but were variants of uncertain biologic significance. STK11 mutations (both frameshift) were identified in 2 of 7 cases (29%); one of these was in a patient with a known history of Peutz-Jeghers syndrome. A mutation in the chromatin remodeling gene ARID1B was identified in 1 of 7 cases (14%). No cases harbored KRAS, NRAS, TP53, PIK3CA, PTEN, or DICER1 mutations. There were relatively low numbers of copy number variations, and no recurrent copy number variations were identified. One case demonstrated moderate copy gain of CCND1. No structural variants were identified. In summary, FATWO is characterized molecularly by the absence of KRAS/NRAS mutations (characteristic of mesonephric carcinoma), absence of DICER1 mutations (characteristic of Sertoli-Leydig cell tumor) and frequent KMT2D mutations of unknown biologic significance. FATWOs exhibit a limited number of molecular aberrations that are significantly different from those reported in tumors in the differential diagnosis, and our results question the relationship of mesonephric carcinoma with FATWO. Disease-defining molecular alterations for FATWO have yet to be discovered.

    View details for DOI 10.1097/PGP.0000000000000545

    View details for PubMedID 30134342

  • Evidence of a Monoclonal Origin for Bilateral Serous Tubal Intraepithelial Neoplasia. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Meserve, E. E., Strickland, K. C., Miron, A., Soong, T. R., Campbell, F., Howitt, B. E., Crum, C. P. 2018

    Abstract

    Serous tubal intraepithelial carcinoma (STIC) is found in 10% to 60% of cases of tuboovarian high-grade serous carcinoma (HGSC) and is presumed to be the site of origin, linking many HGSCs to the fallopian tube. Bilateral STIC is present in 20% of cases. Because clonal Tp53 mutations are a defining feature of HGSC, including their associated STICs, we analyzed 4 cases of bilateral serous tubal intraepithelial neoplasia (STIN), including STIC and Tp53-mutated serous tubal intraepithelial lesions (STILs), associated with HGSC to determine whether they contained the same or different p53 mutations. Extracted DNA from STINs, concurrent HGSCs and control tissues was analyzed for mutations in all exons of Tp53. Sequencing was successful in 3 of the 4 cases, and an identical Tp53 mutation was detected in the HGSC and bilateral STINs in 2 of these 3 cases. One STIN was morphologically a STIL. These findings confirm that a subset of bilateral STINs share the same Tp53 mutation, implying that at least one of the STINs is an intraepithelial metastasis from either the contralateral STIN or HGSC. This study complements others addressing the multiple origins of STIN in the setting of existing HGSC. It further underscores the fact that potential overlap in biologic behavior between STILs and STICs as well as timing and direction of metastatic spread has yet to be resolved.

    View details for DOI 10.1097/PGP.0000000000000534

    View details for PubMedID 29901519

  • Assessment of a Chemotherapy Response Score (CRS) System for Tubo-Ovarian High-Grade Serous Carcinoma (HGSC). International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Ditzel, H. M., Strickland, K. C., Meserve, E. E., Stover, E., Konstantinopoulos, P. A., Matulonis, U. A., Muto, M. G., Liu, J. F., Feltmate, C., Horowitz, N., Berkowitz, R. S., Gupta, M., Hecht, J. L., Lin, D. I., Jochumsen, K. M., Welch, W. R., Hirsch, M. S., Quade, B. J., Lee, K. R., Crum, C. P., Mutter, G. L., Nucci, M. R., Howitt, B. E. 2018

    Abstract

    A chemotherapy response score (CRS) system was recently described to assess the histopathologic response and prognosis of patients with tubo-ovarian high-grade serous carcinoma (HGSC) receiving neoadjuvant chemotherapy. The current study was performed as an independent assessment of this CRS system. We retrospectively identified advanced stage HGSC patients who received neoadjuvant chemotherapy and underwent interval debulking. If available, a hemotoxylin and eosin slide from the omentum and the adnexa was selected for the study. Slides were independently scored by 13 pathologists using the 3-tiered CRS system. Reviewers then received web-based training and rescored the slides. Overall survival and progression-free survival were estimated using the Kaplan-Meier method and compared using the log-rank test. A total of 68 patients with omental (n=65) and/or adnexal (n=59) slides were included in the study. Interobserver reproducibility was moderate for omentum (kappa, 0.48) and poor for adnexa (kappa, 0.40), which improved for omentum (kappa, 0.62) but not for adnexa (kappa, 0.38) after online training. For omental slides, a consensus CRS of 1/2 was associated with a shorter median progression-free survival (10.9mo; 95% confidence interval, 9-14) than a CRS of 3 (18.9mo; 95% CI, 18-24; P=0.020). In summary, a 3-tiered CRS system of hemotoxylin and eosin-stained omental deposits can yield prognostic information for HGSC patients receiving neoadjuvant chemotherapy, and web-based training improved reproducibility but did not alter determination of clinical outcomes. The CRS system may allow oncologists to identify potential nonresponders and triage HGSC patients for heightened observation and/or clinical trials.

    View details for DOI 10.1097/PGP.0000000000000513

    View details for PubMedID 29750700

  • Solitary fibrous tumour of the female genital tract: a clinicopathological analysis of 25 cases HISTOPATHOLOGY Yang, E. J., Howitt, B. E., Fletcher, C. M., Nucci, M. R. 2018; 72 (5): 749–59

    Abstract

    Solitary fibrous tumour (SFT) is an uncommon spindle cell neoplasm of fibroblastic origin, first described as a tumour of the pleura and now well established at extrapleural sites. However, SFT in the female genital tract is rare and therefore not fully characterised. Here, we describe a series of 25 SFTs arising throughout the gynaecological tract, including the vulva (14 cases), vagina (one), cervix (one), uterus (six), ovary (two), and fallopian tube (one).The tumours showed classic histology as well as known variant morphological features, including a fatty component, diffuse stromal hyalinisation, myxoid stroma, and giant-cell angiofibroma-like features. Eleven (11/25, 44%) were considered to be histologically malignant on the basis of mitotic counts of ≥4 per 10 high-power fields. Follow-up data were available for nine (3-56 months; mean 25 months). Six patients are alive with no evidence of disease, and three are alive with disease. Both SFT and other spindle cell lesions of the gynaecological tract were stained for STAT6. Ninety per cent of SFTs showed nuclear expression of STAT6. The majority of other tumour types were negative for STAT6, except for a subset of inflammatory myofibroblastic tumours (1/3; 33%), fibroma/thecoma (3/56; 5%), and sclerosing stromal tumour (1/3; 33%), which showed weak/focal staining.Gynaecological SFT can be diagnosed reliably with careful morphological evaluation and judicious use of immunohistochemical stains, and should be considered in the diagnostic workup of spindle cell tumours of unclear lineage in the female genital tract.

    View details for DOI 10.1111/his.13430

    View details for Web of Science ID 000427248900004

    View details for PubMedID 29106748

  • Mesonephric proliferations of the female genital tract PATHOLOGY Howitt, B. E., Nucci, M. R. 2018; 50 (2): 141–50

    Abstract

    The mesonephric (Wolffian) duct regresses in females during embryological development. Remnants of this duct may persist typically along the lateral walls of the cervix, vagina, adnexa, and uterine corpus. These mesonephric epithelia may expand into hyperplastic proliferations and rarely form neoplasms. The spectrum of morphology, immunophenotype, clinical presentation, and molecular characteristics of mesonephric lesions is reviewed, with attention to distinction from entities in the differential diagnosis.

    View details for DOI 10.1016/j.pathol.2017.11.084

    View details for Web of Science ID 000426351600004

    View details for PubMedID 29269124

  • Targeted Genomic Profiling Reveals Recurrent KRAS Mutations in Mesonephric-like Adenocarcinomas of the Female Genital Tract. The American journal of surgical pathology Mirkovic, J., McFarland, M., Garcia, E., Sholl, L. M., Lindeman, N., MacConaill, L., Dong, F., Hirsch, M., Nucci, M. R., Quick, C. M., Crum, C. P., McCluggage, W. G., Howitt, B. E. 2018; 42 (2): 227–33

    Abstract

    Mesonephric adenocarcinoma most commonly arises in the cervix and is presumed to be derived from normal or hyperplastic mesonephric remnants. It is characterized by recurrent KRAS mutations and lack of PIK3CA/PTEN alterations. Adenocarcinomas of the uterine corpus and ovary characterized by morphologic and immunophenotypic similarities to mesonephric adenocarcinoma have been reported. The pathogenesis of these tumors, which have been designated "mesonephric-like adenocarcinomas" is unknown, and it has been debated whether these represent mesonephric adenocarcinomas that arise in the endometrium/ovary or endometrioid adenocarcinomas that closely mimic mesonephric adenocarcinoma. The relationship at the molecular level between mesonephric adenocarcinomas and mesonephric-like adenocarcinomas is unknown. The aim of this study was to examine the molecular alterations in mesonephric-like adenocarcinomas to identify driver mutations and potential therapeutically targetable mutations, and to determine the relationship between mesonephric-like adenocarcinomas and mesonephric adenocarcinomas using targeted next-generation sequencing. Seven mesonephric-like adenocarcinomas (4 ovarian, 3 uterine corpus) underwent targeted next-generation sequencing to detect mutations, copy number variations and structural variants in exonic regions of 300 cancer genes, and 113 selected intronic regions across 35 genes. All 7 tumors (100%) harbored canonical activating KRAS mutations (4 G12D, 3 G12V). PIK3CA activating mutations were identified in 3 of 7 (43%) cases. There were no alterations in PTEN, ARID1A, or TP53 in any of the tumors. In copy number analysis, 5 of 7 (71%) tumors exhibited 1q gain, which was accompanied by 1p loss in 2 cases. In addition, 4 of 7 (57%) tumors had chromosome 10 gain, which was accompanied by gain of chromosome 12 in 3 cases. Mesonephric-like adenocarcinomas, similar to mesonephric adenocarcinomas, are characterized by recurrent KRAS mutations, gain of 1q, lack of PTEN mutations, and gains of chromosomes 10 and 12. PIK3CA mutations, which have not previously been identified in mesonephric adenocarcinoma, were found in 3 of 7 (43%) mesonephric-like adenocarcinomas in our study. Mesonephric-like adenocarcinomas exhibit strikingly similar molecular aberrations to mesonephric adenocarcinomas, but also frequently harbor PIK3CA mutations, demonstrating biological overlap with carcinomas of both mesonephric and Mullerian (endometrioid) differentiation. Given the previously documented association with endometriosis (ovarian neoplasms) and the prominent endometrial involvement (uterine corpus neoplasms), we believe these are best regarded as of Mullerian origin and representing adenocarcinomas which differentiate along mesonephric lines; as such, we propose the term mesonephric-like Mullerian adenocarcinoma.

    View details for DOI 10.1097/PAS.0000000000000958

    View details for PubMedID 28984674

  • PDGFB Rearrangements in Dermatofibrosarcoma Protuberans of the Vulva: A Study of 11 Cases Including Myxoid and Fibrosarcomatous Variants. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Jahanseir, K., Xing, D., Greipp, P. T., Sukov, W. R., Keeney, G. L., Howitt, B. E., Schoolmeester, J. K. 2018; 37 (6): 537–46

    Abstract

    Dermatofibrosarcoma protuberans (DFSP) is a low-grade fibroblastic sarcoma that tends to arise in young to middle age adults and involve the trunk and proximal extremities. Rare examples of vulvar DFSP have been reported, including myxoid, myoid, and fibrosarcomatous variants, but detection of the characteristic t(17;22)(q22;q13) that produces COL1A1-PDGFB gene fusion has not been evaluated in a large series of primary vulvar tumors. The clinical, morphologic, immunohistochemical, and molecular cytogenetic features of 11 cases were examined. Patient age ranged from 29 to 75 yr (mean, 46 yr; median, 43 yr). Seven tumors were purely classic DFSP, 1 was purely myxoid DFSP and the remaining 3 had varying quantities of fibrosarcomatous DFSP. All cases of classic DFSP had diffuse expression of CD34 and low-level p53 immunoreactivity. Myxoid variants had strong, but reduced expression of CD34. Fibrosarcomatous DFSP showed focal CD34 expression and increased p53 reactivity. Nine of 11 tumors (82%) had rearrangement of PDGFB by fluorescence in situ hybridization. The 2 nonrearranged tumors were a classic DFSP and a myxoid DFSP with fibrosarcomatous transformation. Follow-up was available for 9 patients (82%) and ranged from 1 to 108 mo (mean, 30 mo; median, 21 mo). Eight patients had tumors with positive margins, one of which developed local recurrence after no further therapy. No patient developed metastasis. The high frequency of PDGFB rearrangement in vulvar DFSP provides a useful exploit in diagnostically challenging cases and genetic evidence of probable clinical response to targeted therapeutics in cases of locally advanced or metastatic tumors.

    View details for DOI 10.1097/PGP.0000000000000472

    View details for PubMedID 29140881

    View details for PubMedCentralID PMC5951727

  • WITHDRAWN: International Society of Gynecological Pathologists (ISGyP) Endometrial Cancer Project: Guidelines From the Special Techniques and Ancillary Studies Group. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Cho, K. R., Cooper, K., Croce, S., Djordevic, B., Herrington, S., Howitt, B., Hui, P., Ip, P., Koebel, M., Lax, S., Quade, B. J., Shaw, P., Vidal, A., Yemelyanova, A., Clarke, B., Hedrick Ellenson, L., Longacre, T. A., Shih, I., McCluggage, W. G., Malpica, A., Oliva, E., Parkash, V., Matias-Guiu, X. 2018

    Abstract

    Ahead of Print article withdrawn by publisher.

    View details for DOI 10.1097/PGP.0000000000000496

    View details for PubMedID 29521846

  • Targeted next-generation sequencing in the detection of mismatch repair deficiency in endometrial cancers. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Dong, F., Costigan, D. C., Howitt, B. E. 2018

    Abstract

    Mismatch repair deficiency represents a biomarker of immunotherapy response and a phenotypic feature of Lynch syndrome-associated endometrial cancers. Using a targeted next-generation sequencing assay, we identified molecular features of mismatch repair deficiency, specifically insertion and deletion mutations in mononucleotide repeats, and established thresholds for the number of such mutations to classify endometrial cancers as mismatch repair deficient, proficient, or indeterminate. Sequencing classification was compared to the loss of MLH1, MSH2, MSH6, or PMS2 expression by immunohistochemistry. A total of 259 endometrial cancers were classified by sequencing as mismatch repair deficient (n = 48, 19%), proficient (n = 199, 77%), or indeterminate (n = 12, 5%). Sequencing findings were concordant with loss of expression of at least one mismatch repair protein in 47 of 48 (98%) cases classified as deficient and retained expression of all four proteins in 190 of 199 (95%) cases classified as proficient. Of the 12 cases classified as indeterminate, 7 (58%) demonstrated mismatch repair protein loss. Overall, targeted next-generation sequencing exhibited a high rate of concordance with immunohistochemistry for mismatch repair deficiency; however, sequencing was indeterminate in a few cases and demonstrated a false negative rate of 5%. Although we recommend implementation of a mismatch repair deficiency algorithm for laboratories performing next-generation sequencing cancer panels, immunohistochemistry remains a cost-effective screening method for mismatch repair deficiency in endometrial cancer.

    View details for DOI 10.1038/s41379-018-0125-4

    View details for PubMedID 30206407

  • Frequency of "incidental" serous tubal intraepithelial carcinoma (STIC) in women without a history of or genetic risk factor for high-grade serous carcinoma: A six-year study. Gynecologic oncology Meserve, E. E., Mirkovic, J., Conner, J. R., Yang, E., Muto, M. G., Horowitz, N., Strickland, K. C., Howitt, B. E., Crum, C. P. 2017

    Abstract

    Objective The purpose of this study was to determine the prevalence of incidentally discovered serous tubal intraepithelial carcinoma in women without a genetic risk for or history of high grade serous carcinoma (HGSC) in the gynecologic tract.All pathology reports at our institution that included bilateral salpingectomies from January 2006-December 2011 were examined in women >50years old in which the entire tube or the distal one-third was examined histologically with the complete (proximal and distal fallopian tube) or modified (distal one third of the tube) SEE-FIM protocol. Cases were divided into: Group 1, a history of or known risk factors (BRCA1 or BRCA2 mutations) for HGSC and Group 2, those without these attributes for whom a STIC would be unexpected (incidental). Women undergoing unspecified "risk-reducing" procedures were included in Group 1.Of 4051 identified total, 2268 had complete examination of the distal fallopian tube and were age 50 or above. Of these, 1747 were in group 2. Two STICs were identified (0.1%), one associated with a grade 2 endometrial endometrioid adenocarcinoma and one with a low-grade ovarian serous carcinoma in the setting of a serous borderline tumor.Incidental STICs in women over age 50 are uncommon. However, the significance of lesser tubal atypias (0.3% in this study), risk of STIC in women with no epithelial pathology and the risk imposed by coexisting endometrioid neoplasia are unclear and require further study.

    View details for DOI 10.1016/j.ygyno.2017.04.015

    View details for PubMedID 28479065

  • Universal Screening for Mismatch-Repair Deficiency in Endometrial Cancers to Identify Patients With Lynch Syndrome and Lynch-like Syndrome. International journal of gynecological pathology Watkins, J. C., Yang, E. J., Muto, M. G., Feltmate, C. M., Berkowitz, R. S., Horowitz, N. S., Syngal, S., Yurgelun, M. B., Chittenden, A., Hornick, J. L., Crum, C. P., Sholl, L. M., Howitt, B. E. 2017; 36 (2): 115-127

    Abstract

    Although consensus has yet to be reached on universal mismatch-repair (MMR) protein immunohistochemical (IHC) screening for Lynch syndrome (LS) in endometrial cancer (EC), an increasing number of institutions have adopted universal screening protocols similar to those used for colorectal carcinoma. Here we describe our institution's experience with a prospective universal screening protocol in which all ECs resected over a period of 19 months (n=242) were screened for MLH1, PMS2, MSH2, and MSH6 deficiencies using IHC, followed by MLH1 promoter methylation testing when appropriate. When consent was obtained, tumor samples underwent next-generation sequencing. A total of 11 unmethylated MMR-deficient cases (4.5% of cohort) were identified through IHC screening. Germline testing was performed in 10 cases and confirmed LS in 4 patients (1.7% of cohort). Of our 4 confirmed LS cases, 1 did not meet traditional LS screening criteria (eg, age below 50 y, Revised Bethesda criteria). In addition, universal screening identified 6 germline-negative MMR-deficient nonmethylated cases, 4 of which occurred in women older than 50. Although our next-generation sequencing data suggest somatic mutations in 4 of these cases, it is possible that these cases may represent cases of "Lynch-like syndrome." We conclude that a subset of LS cases could be missed using traditional screening guidelines. The value of screening for Lynch-like syndrome has yet to be determined. Although the cost-effectiveness of universal screening in EC has yet to be elucidated, we conclude that universal IHC screening is currently a reasonable, and arguably superior, approach to screening for LS.

    View details for DOI 10.1097/PGP.0000000000000312

    View details for PubMedID 27556954

  • Cervical mesonephric hyperplasia lacks KRAS/NRAS mutations. Histopathology Mirkovic, J., Schoolmeester, J. K., Campbell, F., Miron, A., Nucci, M. R., Howitt, B. E. 2017; 71 (6): 1003–5

    View details for DOI 10.1111/his.13307

    View details for PubMedID 28703285

  • Involvement of Chromosome 8 in Müllerian Adenosarcoma. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Howitt, B. E., Dal Cin, P., Nucci, M. R., Quade, B. J. 2017; 36 (1): 24–30

    Abstract

    Müllerian adenosarcoma (MA) is an uncommon biphasic neoplasm of the female genital tract, composed of malignant stroma and benign epithelium. Little is known about the molecular and cytogenetic aberrations in MA pathogenesis, including those with progression to sarcomatous overgrowth (SO). Herein, we report all cases of MA in which karyotyping was attempted at our institution. Twenty-one samples from 20 subjects consisted of 15 primary (7 without SO, 8 with SO) and 6 metastatic MA, were cytogenetically investigated in our institution. Karyotypes were successfully obtained in 14/21 (67%) cases and 9 (45%) had cytogenetic aberrations. Two (1 MA with SO and 1 metastatic MA) were markedly complex, displaying extreme aneuploidy with numerous rearrangements. Seven (2 MA without SO, 3 MA with SO, and 2 metastatic MA) demonstrated noncomplex clonal aberrations, of which 5 (71%) included an abnormality involving chromosome 8. Two tumors had rearrangements at 8q13 and another 3 tumors had extra copies of chromosome 8. In 5 cases, a normal karyotype (46,XX) was obtained (2 MA without SO, 2 MA with SO, and 1 metastatic MA). Further study is warranted to explore the genetic mechanism by which chromosome abnormalities, particularly those at 8q13, contribute to MA tumorigenesis.

    View details for DOI 10.1097/PGP.0000000000000287

    View details for PubMedID 26974998

  • Predicted neoantigen load in non-hypermutated endometrial cancers: Correlation with outcome and tumor-specific genomic alterations. Gynecologic oncology reports Shukla, S. A., Howitt, B. E., Wu, C. J., Konstantinopoulos, P. A. 2017; 19: 42–45

    Abstract

    Elevated neoantigen load has been previously correlated with improved outcome and response to immune checkpoint blockade in various tumor types. In endometrial cancer, previous studies of neoantigen load prediction have shown that the hypermutated MSI and POLE-mutated tumors harbor significantly higher predicted neoantigen load compared to the hypomutated CN-low/endometrioid and CN-high/serous-like tumors. Here, we report that predicted neoantigen load may be a prognostic factor in hypomutated endometrial cancers, both in CN-low/endometrioid and CN-high/serous-like tumors. Specifically, in the TCGA dataset, CN-low/endometrioid tumors with neoantigen load in the highest tertile were associated with significantly improved progression free survival (PFS) (p = 0.031), while CN-high/serous-like tumors with neoantigen load in the lowest tertile were associated with worse PFS (p = 0.041). Importantly, certain tumor-specific genomic alterations were enriched in tumors with lower neoantigen load, including CTNNB1 mutations in CN-low/endometrioid tumors and MYC amplification and PIK3CA mutations in CN-high/serous-like tumors. These findings suggest that predicted neoantigen load and specific genomic alterations (such as CTNNB1 mutations, MYC amplification and PIK3CA mutations) may be biomarkers of response to immunotherapy in hypomutated endometrial cancers, and argues that these exploratory biomarkers should be incorporated in clinical trials of immune checkpoint blockade in this disease.

    View details for DOI 10.1016/j.gore.2016.12.009

    View details for PubMedID 28070553

    View details for PubMedCentralID PMC5219603

  • Clear cell ovarian cancers with microsatellite instability: A unique subset of ovarian cancers with increased tumor-infiltrating lymphocytes and PD-1/PD-L1 expression. Oncoimmunology Howitt, B. E., Strickland, K. C., Sholl, L. M., Rodig, S., Ritterhouse, L. L., Chowdhury, D., D'Andrea, A. D., Matulonis, U. A., Konstantinopoulos, P. A. 2017; 6 (2): e1277308

    Abstract

    Clear cell ovarian carcinoma (CCOC) represents a distinct histologic subtype of ovarian cancer associated with significantly worse prognosis across all stages and no effective therapeutic options. Here, we report a rare but clinically important cohort of CCOCs with microsatellite instability (MSI) (MSI-CCOCs), which are highly immunogenic and may thus be very responsive to immune checkpoint blockade. CCOCs with MSI exhibit a significantly higher number of CD8+ TILs, higher CD8+/CD4+ ratio, and higher PD-1+ TILs compared with microsatellite stable (MSS) CCOCs and compared with high grade serous ovarian cancers, which are the most common histologic subtype of ovarian cancer. Of note, PD-L1 expression in tumor cells or immune cells was noted in all cases of CCOCs with MSI. These observations open an alternative therapeutic avenue for a fraction of patients with CCOC and argue for the routine testing of CCOCs for MSI, a test that is not currently routinely performed.

    View details for DOI 10.1080/2162402X.2016.1277308

    View details for PubMedID 28344892

    View details for PubMedCentralID PMC5353914

  • Architectural overlap between benign endocervix and pattern-A endocervical adenocarcinoma: Are all pattern-A tumors invasive? Pathology, research and practice Douglas, G., Howitt, B. E., Schoolmeester, J. K., Schwartz, L., Kos, Z., Islam, S., Djordjevic, B., Parra-Herran, C. 2017; 213 (7): 799–803

    Abstract

    Studies on the pattern-based classification for invasive endocervical adenocarcinoma showed that tumors with nondestructive invasion (pattern-A) have a 0% rate of nodal metastases. Our understanding of pattern-A tumors and their distinction from in-situ adenocarcinoma requires further study. Thirteen sections diagnosed independently as pattern-A adenocarcinoma by three gynecologic pathologists, and 14 sections of benign endocervix were selected. Three additional pathologists (reviewers) evaluated a digital image from each section and classified it as pattern-A or benign based on architecture only. To blind the interpretation to cytologic features, nuclei and cytoplasm were obscured using morphometric software (Zen 2011, Carl Zeiss Microscopy, Germany). 13/27 cases (48%; 8 pattern-A, 5 benign) were correctly classified by all reviewers; 19/27 (70%; 10 pattern-A, 9 benign) were correctly classified by ≥2 reviewers. 3/13 pattern-A cases (23%) were interpreted as benign by ≥2 reviewers. Conversely, 5/14 benign cervices (36%) were misinterpreted as pattern-A by ≥2 reviewers. The number of glands per 20× field was higher in pattern-A cases with high reviewer agreement (p=0.004). An abnormal architecture is seen in many pattern-A adenocarcinomas in support of their invasive nature; some, however, have architecture that overlaps with that of benign endocervix thus may actually represent in-situ lesions. Likewise, normal cervix can be architecturally complex and mirror patterns that pathologists would classify as pattern-A if malignant cytologic features were present. Based on this overlap and the nil risk of nodal spread, an emphasis on the non-destructive, rather than the invasive, nature of pattern-A adenocarcinoma is recommended.

    View details for DOI 10.1016/j.prp.2017.03.008

    View details for PubMedID 28554747

  • Comprehensive Human Papillomavirus Genotyping in Cervical Squamous Cell Carcinomas and Its Relevance to Cervical Cancer Prevention in Malawian Women. Journal of global oncology Howitt, B. E., Herfs, M., Tomoka, T., Kamiza, S., Gheit, T., Tommasino, M., Delvenne, P., Crum, C. P., Milner, D. 2017; 3 (3): 227–34

    Abstract

    Cervical squamous cell carcinoma (SCC) continues to be a significant cause of cancer morbidity and is the third leading cause of cancer-related death in women worldwide. In sub-Saharan Africa, cervical cancer is not only the most common female cancer but also the leading cause of cancer-related deaths in women. Malawi, in particular, has the highest burden of cervical cancer. With the increasing use of human papillomavirus (HPV) vaccination, documenting the prevalent HPV types in those high-risk populations is necessary to both manage expectations of HPV vaccination and guide future vaccine development.In this study, we performed HPV typing on 474 cervical SCC samples and analyzed the potential impact of HPV vaccination in this population.Ninety-seven percent of tumors were positive for at least one HPV type, and 54% harbored more than one HPV type. HPV 16 was the most common type (82%), followed by HPV 18 (34%), HPV 35 (24%), and HPV 31 (12%). A vaccine against HPV 16 and 18 would ideally prevent 53% of cervical SCC, and the nonavalent HPV vaccine (covering HPV 16, 18, 31, 33, 45, 52, and 58) would prevent 71% of cervical SCC in Malawi (assuming 100% vaccine efficacy). The main reason for a lack of coverage was high prevalence of HPV 35, which was also present as a single infection in a small subset of patients.Although any HPV vaccination in this population would likely prevent a significant proportion of cervical cancer, the nonavalent vaccine would provide better coverage. Furthermore, investigation of the role of HPV 35 in this population, including possible cross-protection with other HPV types, should be pursued.

    View details for DOI 10.1200/JGO.2015.001909

    View details for PubMedID 28717764

    View details for PubMedCentralID PMC5493214

  • Differentiated exophytic vulvar intraepithelial lesions are genetically distinct from keratinizing squamous cell carcinomas and contain mutations in PIK3CA. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Watkins, J. C., Howitt, B. E., Horowitz, N. S., Ritterhouse, L. L., Dong, F., MacConaill, L. E., Garcia, E., Lindeman, N. I., Lee, L. J., Berkowitz, R. S., Nucci, M. R., Crum, C. P. 2017; 30 (3): 448–58

    Abstract

    Human papillomavirus-negative keratinizing vulvar cancers typically harbor TP53 mutations as do their precursors, differentiated vulvar intraepithelial neoplasia. However, atypical verruciform proliferations are also associated with these malignancies and their pathogenesis is poorly understood. This study compared 11 atypical verruciform lesions, including atypical verruciform hyperplasia, vulvar acanthosis with altered differentiation, and verruciform lichen simplex chronicus, with 14 human papillomavirus-negative keratinizing squamous cell carcinomas. Extracted tissue DNA was subjected to targeted massively parallel sequencing of the exonic regions of 300 genes. Eight (73%) and six (55%) of eleven atypical verruciform lesions contained mutations in PIK3CA and ARID2, respectively. No TP53 mutations were identified. Eleven (79%) and five (36%) of fourteen keratinizing squamous cell carcinomas tested contained TP53 and CDKN2A mutations, respectively. Keratinizing squamous cell carcinomas displayed the majority of copy number variations with some variations (7p gain and 8p loss) shared by some cases in both groups. One patient developed atypical verruciform lesions with PIK3CA mutations followed by a keratinizing carcinoma with mutations in both PIK3CA and TP53. This study, for the first time segregates atypical verruciform lesions by virtue of a unique genotype (PIK3CA mutant/TP53 wild type) illustrating an example of progression to a TP53-mutated keratinizing carcinoma. The findings indicate that although PIK3CA mutations are found in <10% of vulvar squamous cell carcinomas, they may be specific for a particular pathway involving atypical verruciform lesions, which could function as either a direct precursor or a risk factor for vulvar squamous cell carcinoma. Given the presence of a molecular signature, we propose the term 'differentiated exophytic vulvar intraepithelial lesion' for this group. Whether they function as direct precursors to a less common form of squamous cell carcinoma will require further study, but carcinomas associated with these lesions might warrant testing for PIK3CA mutations to address this question.

    View details for DOI 10.1038/modpathol.2016.187

    View details for PubMedID 27834349

  • Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Uterine Tumors. Surgical pathology clinics Ritterhouse, L. L., Howitt, B. E. 2016; 9 (3): 405–26

    Abstract

    This article focuses on the diagnostic, prognostic, and predictive molecular biomarkers in uterine malignancies, in the context of morphologic diagnoses. The histologic classification of endometrial carcinomas is reviewed first, followed by the description and molecular classification of endometrial epithelial malignancies in the context of histologic classification. Taken together, the molecular and histologic classifications help clinicians to approach troublesome areas encountered in clinical practice and evaluate the utility of molecular alterations in the diagnosis and subclassification of endometrial carcinomas. Putative prognostic markers are reviewed. The use of molecular alterations and surrogate immunohistochemistry as prognostic and predictive markers is also discussed.

    View details for DOI 10.1016/j.path.2016.04.006

    View details for PubMedID 27523969

  • Solitary Fibrous Tumor of the Uterus Presenting With Lung Metastases: A Case Report. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Strickland, K. C., Nucci, M. R., Esselen, K. M., Muto, M. G., Chopra, S., George, S., Howitt, B. E. 2016; 35 (1): 25–29

    Abstract

    We describe the case of an 81-yr-old woman who presented with bilateral pulmonary nodules in the setting of a large uterine mass, concerning for a gynecologic malignancy such as leiomyosarcoma. However, fine-needle aspiration of a lung nodule revealed a spindle cell neoplasm consistent with solitary fibrous tumor (SFT), a rare mesenchymal neoplasm characterized by a patternless architecture of spindle cells and branching ectatic vessels. Total abdominal hysterectomy demonstrated a primary SFT of the uterus. Both the lung lesion and uterine mass were positive for STAT6, a sensitive and specific biomarker for SFT. SFT infrequently metastasizes and only rarely occurs in the uterus. These tumors are considered to have uncertain malignant potential, and the diagnosis of "malignant" SFT requires the presence of >4 mitoses per 10 high-power fields. The uterine SFT we report did not meet this criterion for malignancy, emphasizing that this entity can behave aggressively even without increased mitoses or atypical histology. To our knowledge, this is the first reported case of a uterine SFT with metastasis to the lung. We discuss the differential diagnosis for the finding of multiple pulmonary spindle cell lesions in the setting of a uterine mass.

    View details for DOI 10.1097/PGP.0000000000000197

    View details for PubMedID 26107564

  • Morphologic correlates of molecular alterations in extrauterine Müllerian carcinomas. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Ritterhouse, L. L., Nowak, J. A., Strickland, K. C., Garcia, E. P., Jia, Y., Lindeman, N. I., Macconaill, L. E., Konstantinopoulos, P. A., Matulonis, U. A., Liu, J., Berkowitz, R. S., Nucci, M. R., Crum, C. P., Sholl, L. M., Howitt, B. E. 2016; 29 (8): 893–903

    Abstract

    Extrauterine high-grade serous carcinomas can exhibit various histologic patterns including (1) classic architecture that is papillary, micropapillary and infiltrative and (2) solid, endometrioid, and transitional (ie, SET) patterns. Although the SET pattern has been associated with germline BRCA mutations, potential molecular underpinnings have not been fully investigated. DNA was isolated from 174 carcinomas of the fallopian tube, ovary, or peritoneum. Targeted next-generation sequencing was performed and single-nucleotide and copy number variants were correlated with morphologic subtype. Overall, 79% of tumors were classified as high-grade serous carcinoma (n=138), and the most common mutations in high-grade serous carcinomas were TP53 (94%), BRCA1 (25%), BRCA2 (11%), and ATM (7%). Among chemotherapy-naive high-grade serous carcinomas, 40 cases exhibited classic morphology and 40 cases had non-classic morphology (SET or ambiguous features). Mutations in homologous recombination pathways were seen across all tumor histotypes. High-grade serous carcinomas with homologous recombination mutations were six times more likely to be associated with non-classic histology (P=0.002) and were significantly more likely to be platinum sensitive and have improved progression-free survival (PFS) (P=0.007 and P=0.004, respectively). In a multivariate analysis adjusted for age, homologous recombination mutation status and increased copy number variants were independently associated with improved PFS (P=0.008 and P=0.005, respectively). These findings underscore the potential significance of variant morphologic patterns and comprehensive genomic analysis in high-grade serous carcinomas with potential implications for pathogenesis, as well as response to targeted therapies.

    View details for DOI 10.1038/modpathol.2016.82

    View details for PubMedID 27150160

  • Unusual Mismatch Repair Immunohistochemical Patterns in Endometrial Carcinoma. The American journal of surgical pathology Watkins, J. C., Nucci, M. R., Ritterhouse, L. L., Howitt, B. E., Sholl, L. M. 2016; 40 (7): 909–16

    Abstract

    Universal screening for Lynch syndrome through mismatch repair (MMR) immunohistochemistry (IHC) on tumor samples has brought to light several heterogenous MMR staining patterns. At our institution, a prospective study of universal Lynch syndrome screening using MMR IHC on 125 endometrial cancers (EC) led to the identification of subclonal loss of MMR protein expression within the tumor (n=9). We also interrogated the MMR staining patterns in MMR-deficient EC with concurrent endometrial intraepithelial neoplasia (EIN; n=14) and all mixed-type ECs (n=14) to look for concordant or discordant profiles between the various components. MLH1 promoter methylation and microsatellite instability testing was performed on discordant subclones. Abrupt and complete subclonal loss of MMR expression was identified in 9 cases (7.2%; 7 subclonal MLH1/PMS2 loss, 1 subclonal loss of MLH1 and complete loss of PMS2, and 1 subclonal MSH6 loss). All subclonal MLH1 losses were associated with epigenetic silencing. In cases with concomitant EIN (n=14), 7 cases showed concordant MMR IHC between EC and EIN, and 4 cases showed MMR protein loss confined to the EC. The remaining 3 cases demonstrated subclonal staining in the EIN. In mixed tumors (n=14), subclonal or total MMR IHC deficiency was confined to endometrioid components. In summary, discrete subclonal loss of MMR protein expression occurs in up to 7.2% of EC and, in our experience, only in endometrioid components. Importantly, subclonal MLH1 MMR defects appear to be a biological phenomenon that can be explained by methylation and somatic events, without evidence of underlying germline alterations.

    View details for DOI 10.1097/PAS.0000000000000663

    View details for PubMedID 27186853

  • A BRCA1/2 Mutational Signature and Survival in Ovarian High-Grade Serous Carcinoma. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology Dong, F., Davineni, P. K., Howitt, B. E., Beck, A. H. 2016; 25 (11): 1511–16

    Abstract

    Mutational signatures have been identified by the broad sequencing of cancer genomes and reflect underlying processes of mutagenesis. The clinical application of mutational signatures is not well defined. Here we aim to assess the prognostic utility of mutational signatures in ovarian high-grade serous carcinoma.Open access data of 15,439 somatic mutations of 310 ovarian high-grade serous carcinomas from The Cancer Genome Atlas (TCGA) are used to construct a Bayesian model to classify each cancer as either having or lacking a BRCA1/2 mutational signature. We evaluate the association of the BRCA1/2 signature with overall survival on the TCGA dataset and on an independent cohort of 92 ovarian high-grade serous carcinomas from the Australian Ovarian Cancer Study (AOCS).Patients from TCGA with tumors harboring the BRCA1/2 mutational signature have improved survival (55.2 months vs. 38.0 months), which is independent of BRCA1/2 gene mutation status, age, stage, and grade (HR = 0.64; P = 0.02). In the AOCS dataset, the BRCA1/2 mutational signature is also associated with improved overall survival (46.3 months vs. 23.6 months) independent of age and stage (HR = 0.52; P = 0.007).A BRCA1/2 mutational signature is a prognostic marker in ovarian high-grade serous carcinoma. Mutational signature analysis of ovarian cancer genomes may be useful in addition to testing for BRCA1/2 mutations.This study identifies the use of mutational signatures as a biomarker for survival outcome in ovarian high-grade serous carcinoma. Cancer Epidemiol Biomarkers Prev; 25(11); 1511-6. ©2016 AACR.

    View details for DOI 10.1158/1055-9965.EPI-16-0286

    View details for PubMedID 27496093

  • Mammary-type Myofibroblastoma: Clinicopathologic Characterization in a Series of 143 Cases. The American journal of surgical pathology Howitt, B. E., Fletcher, C. D. 2016; 40 (3): 361–67

    Abstract

    Mammary-type myofibroblastoma (MTMF) is a benign mesenchymal neoplasm initially described to occur in the breast. MTMF is typically CD34 and desmin positive and genetically has rearrangement or deletion of 13q14, resulting in loss of Rb expression by immunohistochemistry (IHC). Although the wider anatomic distribution of MTMF is increasingly recognized, no large series with clinicopathologic information has been reported to date. Archival cases were retrieved, and the diagnosis of MTMF was confirmed. Hematoxylin and eosin-stained slides and IHC slides were reviewed when available (CD34, Desmin, Rb, SMA, S100, EMA, MDM2, CDK4). The patient age, sex, tumor anatomic location and size, preceding symptoms, and margin status were recorded when possible. Clinical follow-up data were requested for tumor recurrence, metastasis, and patient status at last follow-up. A total of 143 cases of MTMF comprised this study, affecting 94 (66%) male and 49 (34%) female individuals. Mean tumor size was 6.6 cm (range, 1 to 22 cm). Anatomic locations included: inguinal/groin region (65; 45%), breast (15; 10%), chest wall/axilla (7; 5%), trunk (17; 12%), lower (18; 13%) and upper (2; 1%) extremities, or intra-abdominal/retroperitoneal (14; 10%). MTMFs were characterized by spindle cells with relatively short, stubby nuclei and a variable adipocytic component. Hyalinization and myxoid stroma were common. Less common morphologic features included nuclear atypia, epithelioid tumor cell morphology, and neurilemmoma-type nuclear palisading. CD34 and desmin were positive in 89% and 91%, respectively, and were both negative in 3%. Rb expression was lost in 92% (57/62). No cases with follow-up data available had tumor recurrence, although 1 case was reportedly a recurrence itself. In summary, MTMF appears more common at extramammary sites than in the breast and can cause diagnostic difficulty when atypia or epithelioid morphology is present or when located in an unusual anatomic location. MTMF is frequently positive for CD34 and desmin by IHC; however, rare cases are negative for both. There is no evidence of any significant recurrence risk for MTMF, even in the presence of positive resection margins. The degree of morphologic overlap between spindle cell lipoma, cellular angiofibroma, and MTMF, in combination with shared genetics and slightly overlapping anatomic distribution, raises the question of whether or not these tumors are truly distinct entities or instead represent points along a single spectrum of genetically related tumors.

    View details for DOI 10.1097/PAS.0000000000000540

    View details for PubMedID 26523539

  • Association and prognostic significance of BRCA1/2-mutation status with neoantigen load, number of tumor-infiltrating lymphocytes and expression of PD-1/PD-L1 in high grade serous ovarian cancer. Oncotarget Strickland, K. C., Howitt, B. E., Shukla, S. A., Rodig, S., Ritterhouse, L. L., Liu, J. F., Garber, J. E., Chowdhury, D., Wu, C. J., D'Andrea, A. D., Matulonis, U. A., Konstantinopoulos, P. A. 2016; 7 (12): 13587–98

    Abstract

    Immune checkpoint inhibitors (e.g., anti-PD-1 and anti-PD-L1 antibodies) have demonstrated remarkable efficacy against hypermutated cancers such as melanomas and lung carcinomas. One explanation for this effect is that hypermutated lesions harbor more tumor-specific neoantigens that stimulate recruitment of an increased number of tumor-infiltrating lymphocytes (TILs), which is counterbalanced by overexpression of immune checkpoints such as PD-1 or PD-L1. Given that BRCA1/2-mutated high grade serous ovarian cancers (HGSOCs) exhibit a higher mutational load and a unique mutational signature with an elevated number of larger indels up to 50 bp, we hypothesized that they may also harbor more tumor-specific neoantigens, and, therefore, exhibit increased TILs and PD-1/PD-L1 expression. Here, we report significantly higher predicted neoantigens in BRCA1/2-mutated tumors compared to tumors without alterations in homologous recombination (HR) genes (HR-proficient tumors). Tumors with higher neoantigen load were associated with improved overall survival and higher expression of immune genes associated with tumor cytotoxicity such as genes of the TCR, the IFN-gamma and the TNFR pathways. Furthermore, immunohistochemistry studies demonstrated that BRCA1/2-mutated tumors exhibited significantly increased CD3+ and CD8+ TILs, as well as elevated expression of PD-1 and PD-L1 in tumor-associated immune cells compared to HR-proficient tumors. Survival analysis showed that both BRCA1/2-mutation status and number of TILs were independently associated with outcome. Of note, two distinct groups of HGSOCs, one with very poor prognosis (HR proficient with low number of TILs) and one with very good prognosis (BRCA1/2-mutated tumors with high number of TILs) were defined. These findings support a link between BRCA1/2-mutation status, immunogenicity and survival, and suggesting that BRCA1/2-mutated HGSOCs may be more sensitive to PD-1/PD-L1 inhibitors compared to HR-proficient HGSOCs.

    View details for DOI 10.18632/oncotarget.7277

    View details for PubMedID 26871470

    View details for PubMedCentralID PMC4924663

  • Genetic Basis for PD-L1 Expression in Squamous Cell Carcinomas of the Cervix and Vulva. JAMA oncology Howitt, B. E., Sun, H. H., Roemer, M. G., Kelley, A., Chapuy, B., Aviki, E., Pak, C., Connelly, C., Gjini, E., Shi, Y., Lee, L., Viswanathan, A., Horowitz, N., Neuberg, D., Crum, C. P., Lindeman, N. L., Kuo, F., Ligon, A. H., Freeman, G. J., Hodi, F. S., Shipp, M. A., Rodig, S. J. 2016; 2 (4): 518–22

    Abstract

    Patients with squamous cell carcinoma (SCC) of the cervix or vulva have limited therapeutic options, and the potential for immunotherapy for this population has not been evaluated. Recent trials suggest that tumors with a genetic basis for PD-1 (programmed cell death protein 1) ligand expression are highly sensitive to therapeutic antibodies targeting PD-1.To determine the genetic status of CD274 (encoding PD-L1 [programmed cell death 1 ligand 1]) and PDCD1LG2 (encoding PD-L2 [programmed cell death 1 ligand 2]) in SCCs of the cervix and vulva and to correlate the findings with PD-L1 protein expression.We performed fluorescence in situ hybridization (FISH) using probes targeting CD274, PDCD1LG2, and the centromeric portion of chromosome 9, and immunohistochemistry (IHC) using an antibody recognizing PD-L1 on formalin-fixed, paraffin-embedded (FFPE) biopsy specimens from 48 cervical SCCs and 23 vulvar SCCs.Tumors were categorized according to the genetic abnormality in CD274 and PDCD1LG2 (coamplification > cogain > polysomy > disomy) as detected by FISH, and evaluated on a semiquantitative scale (modified H score, the product of the percentage of tumor cells with positive staining and the maximum intensity of positive staining) for PD-L1 protein expression as detected by IHC.Overall, 71 samples of FFPE tissue from cases of cervical SCCs (n = 48) and vulvar SCCs (n = 23) were retrieved from the archives of Brigham and Women's Hospital and included in this study. We observed cogain or coamplification of CD274 and PDCD1LG2 in 32 of 48 cervical SCCs (67%) and 10 of 23 vulvar SCCs (43%). Median PD-L1 protein expression was highest among tumors with CD274 and PDCD1LG2 coamplification and lowest among tumors with disomy.Recurrent copy number gain of the genes encoding the PD-1 ligands provides a genetic basis for PD-L1 expression in a subset of cervical and vulvar SCCs and identifies a class of patients that are rational candidates for therapies targeting PD-1.

    View details for DOI 10.1001/jamaoncol.2015.6326

    View details for PubMedID 26913631

  • Pattern-based classification of invasive endocervical adenocarcinoma, depth of invasion measurement and distinction from adenocarcinoma in situ: interobserver variation among gynecologic pathologists. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Parra-Herran, C., Taljaard, M., Djordjevic, B., Reyes, M. C., Schwartz, L., Schoolmeester, J. K., Lastra, R. R., Quick, C. M., Laury, A., Rasty, G., Nucci, M. R., Howitt, B. E. 2016; 29 (8): 879–92

    Abstract

    A pattern-based classification for invasive endocervical adenocarcinoma has been proposed as predictive of the risk of nodal metastases. We aimed to determine the reproducibility of such classification in the context of common diagnostic challenges: distinction between in situ and invasive adenocarcinoma and depth of invasion measurement. Nine gynecologic pathologists independently reviewed 96 cases of endocervical adenocarcinoma (two slides per case). They diagnosed each case as in situ or invasive carcinoma classifying the latter following the pattern-based classification as pattern A (non-destructive), B (focally destructive) or C (diffusely destructive). Depth of invasion, when applicable, was measured (mm). Overall, diagnostic reproducibility of pattern diagnosis was good (κ=0.65). Perfect agreement (9/9 reviewers) was seen in only 11 cases (11%), all destructively invasive (10 pattern C and 1 pattern B). In all, ≥5/9 reviewer concordance was achieved in 82/96 cases (85%). Distinction between in situ and invasive carcinoma, regardless of the pattern, showed only slight agreement (κ=0.37). Likewise, distinction restricted to in situ versus pattern A was poor (κ=0.23). Distinction between non-destructive (in situ+pattern A) and destructive (patterns B+C) carcinoma showed significantly higher agreement (κ=0.62). Estimation of depth of invasion showed excellent reproducibility (ICC=0.82). However, different measurements resulting in differing FIGO stages were common (from at least 1 reviewer in 79% cases). On the basis of interobserver agreement, the pattern-based classification is best at diagnosing destructive invasion, which carries a risk for nodal metastases. Agreement in diagnosing in situ versus invasive carcinoma, including pattern A, was poor. Given the nil risk of nodal spread in in situ and pattern A lesions, the term 'endocervical adenocarcinoma with non-destructive growth' can be considered when the distinction is difficult, after excluding destructive invasion. Depth of invasion measurement was highly reproducible among pathologists; thus, the pattern-based approach can complement, but should not replace, the depth of invasion metric.

    View details for DOI 10.1038/modpathol.2016.86

    View details for PubMedID 27174588

  • Tumors of the Testis: Morphologic Features and Molecular Alterations. Surgical pathology clinics Howitt, B. E., Berney, D. M. 2015; 8 (4): 687–716

    Abstract

    This article reviews the most frequently encountered tumor of the testis; pure and mixed malignant testicular germ cell tumors (TGCT), with emphasis on adult (postpubertal) TGCTs and their differential diagnoses. We additionally review TGCT in the postchemotherapy setting, and findings to be integrated into the surgical pathology report, including staging of testicular tumors and other problematic issues. The clinical features, gross pathologic findings, key histologic features, common differential diagnoses, the use of immunohistochemistry, and molecular alterations in TGCTs are discussed.

    View details for DOI 10.1016/j.path.2015.07.007

    View details for PubMedID 26612222

  • Uterine polyps with features overlapping with those of Müllerian adenosarcoma: a clinicopathologic analysis of 29 cases emphasizing their likely benign nature. The American journal of surgical pathology Howitt, B. E., Quade, B. J., Nucci, M. R. 2015; 39 (1): 116–26

    Abstract

    Müllerian adenosarcoma (MA) is a mixed Müllerian neoplasm composed of malignant stroma and benign epithelium. Endometrial and endocervical polyps are common entities in surgical pathology practice and most can be readily distinguished from MA; however, some have overlapping features, causing diagnostic confusion. In this study, we examined uterine polyps falling short of the diagnosis of MA quantitatively, qualitatively, or both. Our aims were to (1) characterize formally the morphologic features of atypical uterine polyps and (2) determine clinical outcome. Cases were evaluated for morphologic features of MA (phyllodes-like architecture, intraglandular polypoid projections, altered periglandular stroma, and stromal cytologic atypia), and the maximum number of mitoses per 10 high-power fields. The percentage involvement within a polyp by any atypical feature was estimated. The most common change was abnormal architecture, although periglandular stromal abnormalities and increased mitoses were also frequent findings. Stromal cytologic atypia was rare and when present was focal and mild. Histologic follow-up was performed in 24/29 (86%). Two patients had uterine polyps with unusual features similar to those noted on the initial biopsy. The remainder showed either polyp without unusual features or no residual polyp. Clinical follow-up information was available for 28/29 (97%). Twenty-seven of 28 were alive without evidence of disease, whereas 1 patient had died of pancreatic adenocarcinoma. We have shown that uterine polyps with features overlapping with those of MA have a benign clinical course, even with conservative management, as no cases showed progression or malignant transformation.

    View details for DOI 10.1097/PAS.0000000000000303

    View details for PubMedID 25118811

  • Inflammatory myofibroblastic tumor of the uterus: clinical and pathologic review of 10 cases including a subset with aggressive clinical course. The American journal of surgical pathology Parra-Herran, C., Quick, C. M., Howitt, B. E., Dal Cin, P., Quade, B. J., Nucci, M. R. 2015; 39 (2): 157–68

    Abstract

    Inflammatory myofibroblastic tumor is currently regarded as a neoplasm with intermediate biological potential and a wide anatomic distribution. Inflammatory myofibroblastic tumors of the female genital tract are rare, and to date reported cases behaved indolently. We describe, herein, 10 cases of uterine inflammatory myofibroblastic tumor, 3 of which had an aggressive clinical course. Subject age ranged from 29 to 73 years. Tumors were composed of spindle and epithelioid myofibroblastic cells admixed with lymphoplasmacytic infiltrates in a variably myxoid stroma. Two growth patterns, myxoid and fascicular (leiomyoma-like), were noted. All tumors were positive for ALK expression by immunohistochemistry, which was stronger in the myxoid areas. Smooth muscle marker and CD10 expression was variable in extent, but typically positive. Fluorescence in situ hybridization for ALK rearrangements was positive in both fascicular and myxoid areas in all 8 cases tested. Three subjects showed clinical evidence of tumor aggressiveness as defined by extrauterine spread, local recurrence, or distant metastasis. Aggressive tumors were larger, had a higher proportion of myxoid stroma, and higher mitotic activity than indolent tumors. Tumor cell necrosis was seen only in cases with adverse outcome. This is the first report to describe aggressive biological behavior in uterine inflammatory myofibroblastic tumor. This diagnosis is often underappreciated and merits inclusion in the differential diagnosis of myxoid mesenchymal lesions of the uterus, particularly because patients with an aggressive course may benefit from targeted therapy.

    View details for DOI 10.1097/PAS.0000000000000330

    View details for PubMedID 25321329

  • Evidence for a dualistic model of high-grade serous carcinoma: BRCA mutation status, histology, and tubal intraepithelial carcinoma. The American journal of surgical pathology Howitt, B. E., Hanamornroongruang, S., Lin, D. I., Conner, J. E., Schulte, S., Horowitz, N., Crum, C. P., Meserve, E. E. 2015; 39 (3): 287–93

    Abstract

    Most early adnexal carcinomas detected in asymptomatic women with germline BRCA mutations (BRCA) present as serous tubal intraepithelial carcinomas (STIC). However, STICs are found in only ∼40% of symptomatic high-grade serous carcinomas (HGSCs) and less frequently in pseudoendometrioid variants of HGSC. Consecutive cases of untreated HGSC from BRCA and BRCA women with detailed fallopian tube examination (SEE-FIM protocol) were compared. STIC status (+/-) was determined, and tumors were classified morphologically as SET ("SET", >50% solid, pseudoendometrioid, or transitional) or classic predominate ("Classic"). SET tumors trended toward a higher frequency in BRCA versus BRCA women (50% vs. 28%, P=0.11), had a significantly younger mean age than those with classic HGSC in BRCA women (mean 56.2 vs. 64.8 y, P=0.04), and displayed a better clinical outcome in both groups combined (P=0.024). STIC was significantly more frequent in tumors from the BRCA cohort (66% vs. 31%, P=0.017) and specifically the BRCA tumors with classic morphology (83%) versus those with SET morphology (22%, P=0.003). Overall, several covariables-histology, BRCA status, age, coexisting STIC, and response to therapy-define 2 categories of HGSC with differences in precursor (STIC) frequency, morphology, and outcome. We introduce a dualistic HGSC model that could shed light on the differences in frequency of STIC between symptomatic and asymptomatic women with HGSC. This model emphasizes the need for further study of HGSC precursors to determine their relevance to the prevention of this lethal malignancy.

    View details for DOI 10.1097/PAS.0000000000000369

    View details for PubMedID 25581732

  • Association of Polymerase e-Mutated and Microsatellite-Instable Endometrial Cancers With Neoantigen Load, Number of Tumor-Infiltrating Lymphocytes, and Expression of PD-1 and PD-L1. JAMA oncology Howitt, B. E., Shukla, S. A., Sholl, L. M., Ritterhouse, L. L., Watkins, J. C., Rodig, S., Stover, E., Strickland, K. C., D'Andrea, A. D., Wu, C. J., Matulonis, U. A., Konstantinopoulos, P. A. 2015; 1 (9): 1319–23

    Abstract

    Immune checkpoint inhibitor therapy has shown benefit in various cancers, but their potential in endometrial cancer (EC) is unknown.Prediction of neoantigen load was performed using sequencing data from the Cancer Genome Atlas data set. Evaluation of tumor-infiltrating lymphocytes (TILs) and PD-1 and PD-L1 expression was performed in 63 patients with EC referred to our institution. The predicted median (range) neoantigen load (predicted neoepitopes per sample) was proportional to the mutational load: highest in ultramutated polymerase e (POLE) tumors (8342 [628-20 440]), less in hypermutated MSI (541 [146-8063]; P < .001), and lowest in microsatellite-stable tumors (70.5 [7-1877]; P < .001). The POLE and MSI ECs exhibited higher numbers of CD3+ (44.5 vs 21.8; P = .001) and CD8+ (32.8 vs 13.5; P < .001) TILs compared with microsatellite-stable tumors. PD-1 was overexpressed in TILs (81% vs 28%; P < .001) and peritumoral lymphocytes (90% vs 28%; P < .001) of POLE and MSI tumors. PD-L1 expression was infrequently noted in tumor cells but was common in intraepithelial immune cells and more frequent in POLE and MSI tumors (39% vs 13%; P = .02).Polymerase e-mutated and MSI ECs are associated with high neoantigen loads and number of TILs, which is counterbalanced by overexpression of PD-1 and PD-L1. Polymerase e-mutated and MSI EC tumors may be excellent candidates for PD-1-targeted immunotherapies.

    View details for DOI 10.1001/jamaoncol.2015.2151

    View details for PubMedID 26181000

  • Many postchemotherapy sarcomatous tumors in patients with testicular germ cell tumors are sarcomatoid yolk sac tumors: a study of 33 cases. The American journal of surgical pathology Howitt, B. E., Magers, M. J., Rice, K. R., Cole, C. D., Ulbright, T. M. 2015; 39 (2): 251–59

    Abstract

    Sarcomatoid neoplasms in patients with testicular germ cell tumors (TGCTs) may show diverse lineages and are usually attributed to "transformation" of teratoma, although origin from yolk sac tumor (YST) has also been suggested. We evaluated 33 sarcomatoid tumors from 23 TGCT patients that lacked specific features of a defined sarcoma subtype for a number of features, including: atypia (mild, moderate, severe), cellularity, tumor necrosis, mitotic index, stromal vascularity, cell profile (spindle or epithelioid), and stromal quality (myxoid and/or fibrous). Immunohistochemical staining analyses directed against cytokeratin (AE1/AE3), SALL4, glypican-3 (GPC3), α-fetoprotein (AFP), p63, glial fibrillary acidic protein (GFAP), CD34, MUC4, smooth muscle actin (SMA), desmin, caldesmon, and myogenin were performed. Staining intensity (0=negative, 1=weak, 2=moderate, 3=strong) and extent (0=<1%, 1=1% to 10%, 2=10% to 50%, 3=>50%) were scored. Tumor grade based on the French sarcoma grading system was assessed, with grades 2-3 considered high grade. Tumors with at least moderate intensity and >10% (+) cells for both AE1/AE3 and GPC3 were considered to be sarcomatoid YST (SYST); 22 tumors from 14 patients (ages 18 to 38 y, mean 27 y) met these criteria and were the focus of this study. All SYSTs occurred after chemotherapy (3 to 132 mo after TGCT diagnosis; mean 42.5 mo, median 30.5 mo). They had spindled (100%; 19 predominant) and epithelioid cells (77%; 3 predominant) in myxoid to fibrous stroma. Thirteen exhibited at least focally severe nuclear atypia. Distinctive tumor "ringlets" and intercellular basement membrane deposits (parietal YST differentiation) were common. In addition to positivity for AE1/AE3 and GPC3, 15/22 were SALL4 (+), 10/22 were at least focally CD34 (+), and 2/22 were focally p63 (+). Fifty percent exhibited smooth muscle differentiation as evidenced by desmin (8/19), caldesmon (2/4), and/or SMA (4/6) reactivity. AFP, MUC4, GFAP, and myogenin were negative in all cases. On follow-up, 8/14 patients died of disease at 7 to 217 months (mean 58 mo) after the initial SYST diagnosis, whereas 5/14 were alive and had no evidence of disease (ANED) at 1 to 259 months (mean 83 mo). One patient died of unrelated causes at 39 months. Of the 11 patients with high-grade tumors, 8 were dead of disease, 1 died of an unrelated cause, and 2 were ANED; all 3 patients with low-grade tumors were ANED at 41 to 262 months (mean 128 mo). We conclude that a high proportion of sarcomatoid tumors in postchemotherapy resections of TGCT patients are SYSTs. These typically occur several years after diagnosis and behave aggressively when high grade.

    View details for DOI 10.1097/PAS.0000000000000322

    View details for PubMedID 25229769

  • Targeted genomic analysis of Müllerian adenosarcoma. The Journal of pathology Howitt, B. E., Sholl, L. M., Dal Cin, P., Jia, Y., Yuan, L., MacConaill, L., Lindeman, N., Kuo, F., Garcia, E., Nucci, M. R., Quade, B. J. 2015; 235 (1): 37–49

    Abstract

    Müllerian adenosarcoma (MA) is a rare mixed mesenchymal tumour of the female genital tract, composed of malignant stroma and benign-appearing epithelium. Sarcomatous overgrowth (SO) is the only established histological variable associated with higher stage and shorter survival. Specific molecular or immunohistochemistry (IHC) tools for the diagnosis of MA are lacking. Our goal was to study genomic mutations and copy number variations (CNVs) in MA to understand better its pathobiology, and develop specific diagnostic and prognostic tools. DNA was extracted from 20 samples of MA from 18 subjects (12 without SO and 6 with SO), including two in which areas of both typical MA histology and SO were independently tested. Samples were analysed using a targeted next-generation sequencing assay interrogating exonic sequences of 275 cancer genes for mutations and CNVs as well as 91 introns across 30 genes for cancer-associated rearrangements. The mean number of mutations in MA with SO (mean 9.7; range 3-14) did not differ significantly from that in MA without SO (mean 9.6; range 5-16). MA with SO had significantly higher mean numbers of gene-level CNVs (24.6) compared to MA without SO (5; p = 0.0002). The most frequent amplification involved MDM2 and CDK4 (5/18; 28%), accompanied by focal CDK4 and MDM2 and diffuse HMGA2 expression using immunohistochemistry. MYBL1 amplification was seen in 4/18 (22%), predominantly in SO. Alterations in PIK3CA/AKT/PTEN pathway members were seen in 13/18 (72%). Notably, TP53 mutations were uncommon, present in only two cases with SO. Three out of 18 (17%) had mutations in ATRX, all associated with SO. No chromosomal rearrangements were identified. We have identified a number of recurrent genomic alterations in MA, including some associated with SO. Although further investigation of these findings is needed, confirmation of one or more may lead to new mechanistic insights and novel markers for this often difficult-to-diagnose tumour.

    View details for DOI 10.1002/path.4442

    View details for PubMedID 25231023

  • GATA3 Is a Sensitive and Specific Marker of Benign and Malignant Mesonephric Lesions in the Lower Female Genital Tract. The American journal of surgical pathology Howitt, B. E., Emori, M. M., Drapkin, R., Gaspar, C., Barletta, J. A., Nucci, M. R., McCluggage, W. G., Oliva, E., Hirsch, M. S. 2015; 39 (10): 1411–19

    Abstract

    GATA3 is a transcription factor critical for embryogenesis, development, and cell differentiation. Recent studies have suggested that GATA3 is a sensitive and relatively specific biomarker for urothelial and breast carcinomas, with most Müllerian carcinomas being negative. We investigated GATA3 expression in mesonephric/Wolffian remnants and tumors in the female genital tract. A western blot was performed to assess specificity for the GATA3 antibody. GATA3 immunohistochemistry was performed on 59 formalin-fixed paraffin-embedded mesonephric samples, including 17 mesonephric remnants (MR; 11 cervical and 6 fallopian tube), 15 mesonephric hyperplasias, 21 mesonephric carcinomas, and 6 female adnexal tumors of probable Wolffian origin. Thirty conventional endocervical adenocarcinomas (ENDO-CA), 9 gastric-type cervical adenocarcinomas, and 165 endometrial adenocarcinomas (EM-CA) were also evaluated. GATA3 nuclear intensity and extent of staining was evaluated. The western blot revealed GATA3 expression in seminal vesicle and cell lines derived from breast and urothelial carcinomas, but not in other cell lines including ovarian, cervical, and endometrial cancers. All cervical MRs and mesonephric hyperplasias, 5/6 (83%) fallopian tube MRs, and 20/21 (95%) mesonephric carcinomas were GATA3 positive, although with great variability in both intensity (weak to strong) and extent (1+ to 3+) of staining. Only 1/6 (17%) female adnexal tumors of probable Wolffian origin showed weak multifocal staining. One of 30 (3%) usual-type ENDO-CAs and 3/165 EM-CAs exhibited weak-moderate GATA3 immunoreactivity; all gastric-type cervical adenocarcinomas were negative. GATA3 is a highly sensitive and specific marker for mesonephric lesions in the lower genital tract; however, its utility in the upper genital tract may be more limited. In addition, GATA3 can aid in distinguishing lower genital mesonephric lesions from usual-type and gastric-type ENDO-CAs and uterine EM-CAs.

    View details for DOI 10.1097/PAS.0000000000000471

    View details for PubMedID 26135559

  • Targeted genomic profiling reveals recurrent KRAS mutations and gain of chromosome 1q in mesonephric carcinomas of the female genital tract. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Mirkovic, J., Sholl, L. M., Garcia, E., Lindeman, N., MacConaill, L., Hirsch, M., Dal Cin, P., Gorman, M., Barletta, J. A., Nucci, M. R., McCluggage, W. G., Howitt, B. E. 2015; 28 (11): 1504–14

    Abstract

    Mesonephric carcinoma is a rare form of gynecologic cancer derived from mesonephric remnants usually located in the lateral wall of the uterine cervix. An analogous tumor occurs in the adnexa, female adnexal tumor of probable Wolffian origin. The pathogenesis and molecular events in mesonephric carcinoma are not known. The aim of this study was to examine the molecular alterations in mesonephric carcinoma to identify driver mutations and therapeutically targetable mutations. This study consisted of 19 tumors from 17 patients: 18 mesonephric carcinomas (15 primary tumors and three metastatic tumors) and 1 female adnexal tumor of probable Wolffian origin. In two patients, both primary and metastatic tumors were available. Genomic DNA was isolated and targeted next-generation sequencing was performed to detect mutations, copy number variations, and structural variants by surveying full exonic regions of 300 cancer genes and 113 selected intronic regions across 35 genes. Fluorescence in situ hybridization (FISH) for 1p and 1q was performed in two cases. Eighty-one percent (13/16) of mesonephric carcinomas had either a KRAS (n=12) or NRAS (n=1) mutation. Mutations in chromatin remodeling genes (ARID1A, ARID1B, or SMARCA4) were present in 62% of mesonephric carcinomas. All mesonephric carcinomas lacked mutations in PIK3CA and PTEN. The most common copy number alteration was 1q gain, found in 12 (75%) mesonephric carcinomas; this was confirmed by FISH in two cases. Mesonephric carcinoma is characterized by molecular alterations that differ from those of more common variants of cervical and endometrial adenocarcinoma, which harbor KRAS/NRAS mutations in 7% and 25% of cases, respectively. KRAS/NRAS mutations are common in mesonephric carcinoma and are often accompanied by gain of 1q and mutations in chromatin remodeling genes. Targeting inhibitors of the RAS/MAPK pathway may be useful in the treatment of mesonephric carcinoma.

    View details for DOI 10.1038/modpathol.2015.103

    View details for PubMedID 26336887

  • Perivascular epithelioid cell neoplasm (PEComa) of the gynecologic tract: clinicopathologic and immunohistochemical characterization of 16 cases. The American journal of surgical pathology Schoolmeester, J. K., Howitt, B. E., Hirsch, M. S., Dal Cin, P., Quade, B. J., Nucci, M. R. 2014; 38 (2): 176–88

    Abstract

    Perivascular epithelioid cell tumor (PEComa) belongs to a family of tumors characterized by coexpression of melanocytic and muscle markers. Recent studies have shown that sporadic and tuberous sclerosis complex-associated PEComa may respond to mTOR inhibitors underscoring the importance of recognizing this tumor. However, its occurrence in the gynecologic tract continues to be disputed owing to its common misclassification as other types of uterine sarcoma and its controversial relationship with epithelioid smooth muscle tumors. To more fully characterize PEComa of the female genital tract, 16 cases of gynecologic PEComa were identified (1990 to 2012) and formed the basis of this study. Each case was analyzed for conventional morphologic and immunohistochemical characteristics established for PEComa of extrauterine sites; clinical outcome data were obtained for all cases. The 16 patients were aged 28 to 60 (mean 49; median 50) years, and 1 had a history of tuberous sclerosis complex. Thirteen cases were primary of the uterus, 2 of the adnexa, and 1 of the vagina. Tumor size ranged from 0.3 to 25.0 (mean 8.7) cm. Three patients died of disease, 6 were alive with disease, and 7 were alive without evidence of disease at last follow-up (1 mo to 13 y follow-up; mean 26 mo). All patients with an adverse outcome met established criteria for malignancy as proposed for extrauterine sites (ie, 2 or more features present: size ≥5 cm, high-grade nuclear features, infiltration, necrosis, lymphovascular invasion, or a mitotic rate ≥1/50 high-power fields). Of the melanocytic markers, HMB45 was most commonly expressed (16/16 positive, 100%), followed by microphthalmia transcription factor (11/12 positive, 92%), MelanA (14/16 positive, 88%), and S100 protein (2/10 positive, 20%). Of the smooth muscle markers, desmin was most commonly expressed (15/15 cases, 100%), followed by SMA (14/15 cases, 93%) and h-caldesmon (11/12 cases, 92%). TFE3 immunopositivity was identified in 5 of 13 cases; however, 3 tested cases were negative for a TFE3 rearrangement by fluorescence in situ hybridization. Current criteria for malignancy appear to be valid in the female genital tract, although modified criteria, as described herein, may be more specific. Awareness of the characteristic features of PEComa is important to help distinguish it from epithelioid smooth muscle tumors and other mimics as PEComa may respond to unique chemotherapeutic regimens.

    View details for DOI 10.1097/PAS.0000000000000133

    View details for PubMedID 24418852

  • Identification and Characterization of 2 Testicular Germ Cell Markers, Glut3 and CyclinA2 APPLIED IMMUNOHISTOCHEMISTRY & MOLECULAR MORPHOLOGY Howitt, B. E., Brooks, J. D., Jones, S., Higgins, J. P. 2013; 21 (5): 401-407

    Abstract

    Testicular germ cell tumors (TGCT) are the most common type of testicular tumor and encompass different histologic types that greatly influence treatment and prognosis. Immunohistochemical studies may be required for accurate classification, particularly when these tumors present at extragonadal sites, and to aid in distinguishing histologic types. Traditional markers for identifying and distinguishing TGCT include PLAP, CD117, AFP, and CD30. More recently, the addition of OCT3/4 and SALL4 has increased sensitivity for immunohistochemical detection of germ cell tumors. We examined gene expression data from a previously published microarray study that compared normal testis mRNA expression to various TGCT. We also performed a search of the literature to identify less well-characterized markers. Glut3 and cyclinA2 showed promise as TGCT markers. Therefore, we evaluated expression of glut3 and cyclinA2 by immunohistochemistry using tissue microarrays (TMAs). Of 66 seminomas included in the TMA, 64 (97%) showed positive nuclear staining for cyclinA2 and 58 (88%) were strongly positive. Strong positive staining for cyclinA2 was also seen in the spermatocytic seminoma. All 20 of the embryonal carcinomas stained positively with cyclinA2, and 19 (95%) displayed strong nuclear staining for cyclinA2. Twenty of the 20 embryonal carcinomas stained for glut3 in a strong membranous pattern. Of 8 yolk sac tumors, 100% stained with glut3. We also evaluated glut3 and cyclinA2 staining on a general TMA containing 486 samples representing 156 different tumors. CyclinA2 stained a number of other tumor types, but the majority of these were weak or focal staining. Glut3 was rarely positive in other tumors; interestingly, most of these were of ovarian origin. We conclude that glut3 is a sensitive (96%) and specific (92%) marker for embryonal carcinomas and yolk sac tumors. Although cyclinA2 is a sensitive marker of seminomas and embryonal carcinomas (98%), its specificity is lower if focal and weak staining of nongerm cell tumors is considered positive. The sensitivity and specificity of glut3 are comparable with that seen for SALL4.

    View details for DOI 10.1097/PAI.0b013e31827b505f

    View details for Web of Science ID 000324837800004

    View details for PubMedID 23343953

  • Through the glass darkly: intraepithelial neoplasia, top-down differentiation, and the road to ovarian cancer. The Journal of pathology Crum, C. P., Herfs, M., Ning, G., Bijron, J. G., Howitt, B. E., Jimenez, C. A., Hanamornroongruang, S., McKeon, F. D., Xian, W. 2013; 231 (4): 402–12

    Abstract

    It is currently hoped that deaths from extra-uterine high-grade serous cancer (HGSC) will be reduced via opportunistic salpingectomy in healthy women. Accumulated data implicate the fimbria as a site of origin and descriptive molecular pathology and experimental evidence strongly support a serous carcinogenic sequence in the Fallopian tube. Both direct and indirect ('surrogate') precursors suggest that the benign tube undergoes important biological changes after menopause, acquiring abnormalities in gene expression that are often shared with malignancy, including PAX2, ALDH1, LEF1, RCN1, RUNX2, beta-catenin, EZH2, and others. However, the tube can be linked to only some HGSCs, recharging arguments that nearby peritoneum/ovarian surface epithelium (POSE) also hosts progenitors to this malignancy. A major sticking point is the difference in immunophenotype between POSE and Müllerian epithelium, essentially requiring mesothelial to Müllerian differentiation prior to or during malignant transformation to HGSC. However, emerging evidence implicates an embryonic or progenitor phenotype in the adult female genital tract with the capacity to differentiate, normally or during neoplastic transformation. Recently, a putative cell of origin for cervical cancer has been identified in the squamo-columnar (SC) junction, projecting a model whereby Krt7+ embryonic progenitors give rise to immunophenotypically distinct progeny under stromal influences via 'top down' differentiation. Similar differentiation can be seen in the endometrium with a parallel in juxtaposed mesothelial and Müllerian differentiation in the ovary. Abrupt mesothelial-Müllerian transitions remain to be proven, but would explain the rapid evolution, short asymptomatic interval, and absence of a defined epithelial starting point in many HGSCs. Resolving this question will require accurately distinguishing progenitor from progeny tumour cells in HGSC and pinpointing where initial transformation and trans-differentiation occur, whether in the tube or POSE. Both will be critical to expectations from prophylactic salpingectomy and future approaches to pelvic serous cancer prevention.

    View details for DOI 10.1002/path.4263

    View details for PubMedID 24030860

    View details for PubMedCentralID PMC3947463

  • Intestinal-type endocervical adenocarcinoma in situ: an immunophenotypically distinct subset of AIS affecting older women. The American journal of surgical pathology Howitt, B. E., Herfs, M., Brister, K., Oliva, E., Longtine, J., Hecht, J. L., Nucci, M. R. 2013; 37 (5): 625–33

    Abstract

    Conventional endocervical adenocarcinoma in situ (cAIS) is typically strongly and diffusely positive for p16 with a high Ki67 index consistent with its frequent association with high-risk human papillomavirus (HPV) infection. The intestinal variant (iAIS) is less common, and its relationship to HPV infection has not been thoroughly examined. This study compares the clinicopathologic features, frequency of HPV infection, and expression of CDX2 and surrogate biomarkers of HPV infection (p16, Ki67) in cAIS with those of iAIS. A total of 86 cases with a diagnosis of AIS (49 iAIS, 37 cAIS) were identified from our multi-institutional files. Of these, 13 iAIS and 20 cAIS cases had slides and tissue available for histopathologic review, immunohistochemical analysis, and molecular tests. All 86 cases were used to evaluate clinical parameters; however, HPV DNA analysis and immunohistochemical analysis for p16, MIB-1, CDX2, and p53 were performed only on those cases with available slides or paraffin blocks. The average age at diagnosis was significantly higher in iAIS compared with that in cAIS (44.5 vs. 32.6 y) (P=0.0001). All 20 cAIS cases showed moderate to strong and diffuse p16 staining; however, only 9/13 iAIS cases showed this degree of p16 staining, whereas 4/13 (31%) iAIS cases showed weak and patchy distribution (P<0.02). Only 6/9 (67%) iAIS cases were positive for either HPV type 18 (5) or 33 (1), in contrast to 11/11 conventional cAIS (P=0.04). Similarly, 12/14 cAIS, but only 5/13 iAIS, cases showed a high Ki67 proliferative index. CDX2 was positive in all iAIS cases, whereas p53 was negative. Most iAIS cases are positive for high-risk HPV and show moderate to strong and diffuse p16 staining; however, a subset of iAIS shows variable staining with p16 and Ki67, is not associated with HPV, and occurs in a distinctly older age group suggesting an alternative pathogenesis. Awareness that iAIS can show variable staining for p16 and Ki67 is important when resolving problematic endocervical lesions, particularly in small biopsies with unusual p16 staining patterns.

    View details for DOI 10.1097/PAS.0b013e318285be00

    View details for PubMedID 23552379

  • Stathmin-1 expression as a complement to p16 helps identify high-grade cervical intraepithelial neoplasia with increased specificity. The American journal of surgical pathology Howitt, B. E., Nucci, M. R., Drapkin, R., Crum, C. P., Hirsch, M. S. 2013; 37 (1): 89–97

    Abstract

    A fundamental controversy in using biomarkers to diagnose cervical cancer precursors [ie, squamous intraepithelial lesions (SIL)] is their lack of specificity for high-grade SIL [HSIL; cervical intraepithelial neoplasia grade 2/3 (CIN2/3)]. Stathmin-1 (STMN), a microtubule-destabilizing protein important in mitosis, is overexpressed in a variety of malignancies including those from the Müllerian tract and may be associated with poor outcome. However, the use of STMN as a diagnostic marker in cervical SILs has not been explored. A total of 193 cervical samples, including benign cervix and squamous and glandular lesions, were evaluated for STMN, p27 (a known cell cycle regulator inversely expressed with STMN in normal and many neoplastic tissues), p16, and Ki67 expression by immunohistochemical analysis. SILs were independently scored and classified as benign, low-grade SIL (LSIL/CIN1), and HSIL (separated into CIN2 or CIN3) on the basis of a majority diagnosis. Each diagnosis was correlated with biomarker expression independent of hematoxylin and eosin review. STMN was normally expressed in basal cells of the ectocervix and was absent in benign endocervix;"positive" STMN staining was defined as immunoreactivity in at least two thirds of the epithelial thickness. A majority hematoxylin and eosin diagnosis was obtained in 189/193 cases on initial independent review, with squamous epithelia ultimately classified as benign, CIN1, CIN2, and CIN3 in 25, 56, 11, and 16 cases, respectively. STMN was positive in 5/56 (9%) CIN1, 5/11 (45%) CIN2, 14/15 (93%) CIN3, all adenocarcinoma in situ (19/19), and all invasive squamous cell carcinoma (32/32) and adenocarcinoma (34/34) cases. In contrast, 40/56 (71%) CIN1, 11/11 (100%) CIN2, and 15/16 (94%) CIN3 lesions were p16 positive (defined as diffuse block staining in at least one third of the epithelial thickness). One CIN3 was negative for both p16 and STMN. Ki67 and p27 staining was variable in squamous lesions. These results demonstrate that STMN is overexpressed in virtually all cervical carcinomas and CIN3 lesions. In contrast to p16, which often stains LSIL and a small subset of reactive biopsies, STMN has greater specificity for CIN3 and has the potential to distinguish these latter lesions from the majority of low-grade precursors and negative/reactive cervical biopsies. STMN overexpression appears independent of proliferation, maturation, and human papilloma virus cytopathic effect and may be useful diagnostically in identifying HSIL. Further studies correlating STMN staining with lesion persistence or morphologic progression, in the context of CIN grade, are warranted.

    View details for DOI 10.1097/PAS.0b013e3182753f5a

    View details for PubMedID 23211296

  • A novel blueprint for 'top down' differentiation defines the cervical squamocolumnar junction during development, reproductive life, and neoplasia. The Journal of pathology Herfs, M., Vargas, S. O., Yamamoto, Y., Howitt, B. E., Nucci, M. R., Hornick, J. L., McKeon, F. D., Xian, W., Crum, C. P. 2013; 229 (3): 460–68

    Abstract

    The cervical squamocolumnar (SC) junction is the site of a recently discovered 'embryonic' cell population that was proposed as the cell of origin for cervical cancer and its precursors. How this population participates in cervical remodelling and neoplasia is unclear. In the present study, we analysed the SC junction immunophenotype during pre- and post-natal human and mouse development and in the adult, processes of metaplastic evolution of the SC junction, microglandular change, and early cervical neoplasia. Early in life, embryonic cervical epithelial cells were seen throughout the cervix and subsequently diminished in number to become concentrated at the SC junction in the adult. In all settings, there was a repetitive scenario in which cuboidal embryonic/SC junction cells gave rise to subjacent metaplastic basal/reserve cells with a switch from the SC junction positive to negative immunophenotype. This downward or basal (rather than upward or apical) evolution from progenitor cell to metaplastic progeny was termed reverse or 'top down' differentiation. A similar pattern was noted in high-grade squamous intraepithelial lesions (HSILs), suggesting that HPV infection of the cuboidal SC junction cells initiated outgrowth of basally-oriented neoplastic progeny. The progressive loss of the embryonic/SC junction markers occurred with 'top down' differentiation during development, remodelling, and early neoplasia. Interestingly, most low-grade SILs were SC junction-negative, implying infection of metaplastic progeny rather than the original SC junction cells. This proposed model of 'top down' differentiation resolves the mystery of how SC junction cells both remodel the cervix and participate in neoplasia and provides for a second population of metaplastic progeny (including basal and reserve cells), the infection of which is paradoxically less likely to produce a biologically aggressive precursor. It also provides new targets in animal models to determine why the SC junction is uniquely susceptible to carcinogenic HPV infection.

    View details for DOI 10.1002/path.4110

    View details for PubMedID 23007879

  • Oncogenic mutations in cervical cancer: genomic differences between adenocarcinomas and squamous cell carcinomas of the cervix. Cancer Wright, A. A., Howitt, B. E., Myers, A. P., Dahlberg, S. E., Palescandolo, E., Van Hummelen, P., MacConaill, L. E., Shoni, M., Wagle, N., Jones, R. T., Quick, C. M., Laury, A., Katz, I. T., Hahn, W. C., Matulonis, U. A., Hirsch, M. S. 2013; 119 (21): 3776–83

    Abstract

    Cervical cancer is the second leading cause of cancer deaths among women worldwide. The objective of this study was to describe the most common oncogenic mutations in cervical cancers and to explore genomic differences between the 2 most common histologic subtypes: adenocarcinoma and squamous cell carcinoma.A high-throughput genotyping platform, termed Oncomap, was used to interrogate 80 cervical tumors for 1250 known mutations in 139 cancer genes. Samples were analyzed using a mass spectrometry-based genotyping platform and were validated using orthogonal chemistry. Epidermal growth factor receptor (EGFR) mutations were further validated by massive parallel sequencing. Human papilloma virus (HPV) genotyping also was performed.Validated mutations were detected in 48 of 80 tumors (60%) examined. The highest mutation rates were in the genes phosphatidylinositol 3-kinase, catalytic subunit α (PIK3CA) (31.3%); Kirsten rat sarcoma viral oncogene homolog (KRAS) (8.8%); and EGFR (3.8%). PIK3CA mutation rates did not differ significantly between adenocarcinomas and squamous cell carcinomas (25% vs 37.5%, respectively; P = .33). In contrast, KRAS mutations were identified only in adenocarcinomas (17.5% vs 0%; P = .01), and a novel EGFR mutation was detected only in squamous cell carcinomas (0% vs 7.5%; P = .24). There were no associations between HPV-16 or HPV-18 and somatic mutations or overall survival. In adjusted analyses, PIK3CA mutations were associated with shorter survival (67.1 months vs 90.3 months; hazard ratio, 9.1; 95% confidence interval, 2.8-29.5 months; P < .001).Cervical cancers harbor high rates of potentially targetable oncogenic mutations. In addition, cervical squamous cell carcinoma and adenocarcinoma have distinct molecular profiles, suggesting that clinical outcomes may be improved with the use of more tailored treatment strategies, including PI3K and MEK inhibitors.

    View details for DOI 10.1002/cncr.28288

    View details for PubMedID 24037752

    View details for PubMedCentralID PMC3972000