Andrew R. Hoffman

The laboratory is interested in examining the role of insulin-like growth factors (IGF) in normal physiology and in oncogenesis. We are studying the molecular biology and physiology of IGF with an emphasis on the following areas:

1) We have shown that the IGF2 gene is parentally imprinted in most normal tissues, but that in some malignant neoplasms, the gene is biallelically expressed. Our inital work has concentrated on IGF2 gene expression in normal and neoplastic liver, kidney, uterine and breast tissues, where we have shown that the gene is overexpressed. Moreover, in nearly half of these tumors, IGF2 genomic imprinting is relaxed, leading to biallelic expression of the autocrine growth factor.
2) During our investigation of the mechanism for IGF2 imprinting, we have discovered that the imprinting process is promoter-specific, i.e., transcripts derived from promoters P2-P4 are imprinted while transcripts from promoter P1 are not imprinted. We are actively investigating the role of DNA and histone methylation in genomic imprinting.
3) Our group has actively studied the role of GH and IGF-I on body composition and exercise tolerance. We now plan to investigate the efficacy and safety of testosterone replacement in elderly men.