Current Research and Scholarly Interests
Dr. John has extensive expertise in conducting population-based epidemiologic studies and has led as Principal Investigator multiple large-scale studies, including multi-center studies with a study site in the San Francisco Bay Area with its diverse population. Many of her studies and collaborations investigated cancer health disparities. Her research has focused on the role of modifiable lifestyle factors (e.g., body size, physical activity, diet), hormonal factors, early-life exposures, genetic variants, and gene-environment interactions; differences in risk factors by race and ethnicity, breast cancer subtypes, and prostate cancer subtypes; risk factors for familial breast cancer and second primary breast cancer, as well as prognostic factors related to survival disparities.
As Principal Investigator, Dr. John has led a number of studies conducted in the San Francisco Bay Area, including:
- the Northern California site of the Breast Cancer Family Registry, an on-going prospective multi-generational cohort of over 13,000 families established in 1995 at six international sites;
- the San Francisco Bay Area Breast Cancer Study, a population-based case-control study in nearly 5,000 African American, Hispanic, and non-Hispanic White women that investigated the role of modifiable lifestyle factors and other risk factors;
- the California site of the Breast Cancer Health Disparities Study that investigated genetic variability and breast cancer risk and survival in Hispanic and non-Hispanic White populations in the context of genetic admixture;
- the Breast Cancer Etiology in Minorities (BEM) Study, a pooled analysis of risk factors for breast cancer subtypes in minoritized racial and ethnic populations;
- the Northern California site of the WECARE Study that investigates risk factors for second primary contralateral breast cancer;
- the Second Primary Breast Cancer Disparities Study, a pooled analysis of risk factors for contralateral and ipsilateral second primary breast cancer in a diverse population;
- the San Francisco Bay Area Prostate Cancer Study, a population-based case-control study of lifestyle and genetic risk factors for advanced and localized disease.
These studies collected and pooled extensive data and biospecimens and continue to support numerous ancillary studies, collaborations and international consortia and have contributed to a better understanding of cancer risk and survival in minoritized racial and ethnic populations.
Dr. John is a founding PI of the LEGACY Girls Study, a prospective cohort established in 2011 that investigates early life exposures in relation to pubertal development outcomes, breast tissue characteristics, and behavioral and psychosocial outcomes in the context of having a family history or breast cancer.
In 2023, Dr. John joined the Stanford investigator team of the MOSAAIC (The Multiethnic Observational Study in American Asian and Pacific Islander Communities) Study, a five-center study to improve health of American Asian, Native Hawaiian, and Pacific Islander populations.
