Thomas E. Rohan, MD, PhD

2012-2013 BCRF Project:
Benign proliferative breast disease (BPBD) is a putative breast cancer precursor; however, the etiology of BPBD is poorly characterized. A greater understanding of the molecular pathways that play a role in the development of BPBD might enhance current understanding of the origins of breast cancer and may help identify women who would benefit from increased surveillance and screening.

Also, obesity is a positive risk factor for postmenopausal breast cancer, and several obesity-related molecular pathways - namely, hyperinsulinemia, estrogen, and inflammation - have been implicated in breast tumorigenesis. Given that the hallmark of BPBD is epithelial proliferation, and that a common characteristic of each of these obesity-related pathways is pro-proliferative activity, Dr. Rohan's team hypothesizes that hyperinsulinemia, estrogen, and inflammation might be etiologically relevant to BPBD development. To test this hypothesis, Dr. Rohan proposes to prospectively investigate the independent associations of fasting insulin, estradiol, CRP, and adiponectin with the incidence of BPBD. Specifically, using cases of BPBD identified previously in the Women's Health Initiative (WHI) clinical trial, Dr. Rohan's team will conduct a study involving 700 cases of BPBD (297 with atypical hyperplasia and 403 BPBD without atypia) and 1,400 matched controls (women free of any benign breast disease). Their specific aims are to: (i) investigate the independent associations of baseline fasting insulin, estradiol, C-reactive protein, and adiponectin with risk of benign proliferative breast disease among women enrolled in WHI; and (ii) evaluate whether the associations of insulin, estradiol, C-reactive protein, and adiponectin with BPBD differ according to the presence or absence of atypical hyperplasia.

In addition, Dr. Rohan's team will continue with the Canadian Study of Diet, Lifestyle, and Health, a prospective study that includes ~39,000 women. The researchers will undertake a linkage of the cohort to the Ontario Cancer Registry, enter questionnaire data for the additional (~250) breast cancer cases expected to be identified, continue with analysis of data from the cohort, and test the feasibility of collection of tumor blocks for the breast cancer cases.

Mid-year Progress: For the component of their project focused on benign proliferative breast disease (BPBD) and being conducted as a nested case-control study in the Women's Health Initiative Clinical Trial, Dr. Rohan's team has selected the cases and the corresponding matched controls. The serum samples for these subjects were aliquoted in early January and shipped to Einstein in mid-January. The researchers expect the laboratory assays to be completed by the end of April and anticipate that it will then take about one month to assemble the data file for the project, after which the statistical analysis will commence. With respect to their ongoing cohort study, the Canadian Study of Diet, Lifestyle, and Health, Dr. Rohan recently completed a linkage of the cohort to the Canadian Cancer Registry which resulted in identification of 1,110 breast cancer cases, and questionnaires for 900 of these subjects have now been entered. Also, they recently updated their linkage to the Ontario Cancer Registry and ascertained an additional 170 breast cancer cases; questionnaires for 120 of these subjects have been entered to date. Once data entry has been completed -- expected within the next two to three months -- Dr. Rohan's team will be in a position to commence analyses of dietary and lifestyle factors in relation to breast cancer risk in a study with 1,280 breast cancer cases and 3,339 subcohort members.

Bio:
Dr. Rohan received his MD (awarded as M.B., B.S.) from the University of Adelaide, MS degrees in Epidemiology and in Medical Statistics from the London School of Hygiene and Tropical Medicine (University of London), and a PhD in Epidemiology from the University of Adelaide. After stints at St. Bartholomew's Hospital and with the Medical Research Council in London, England, and at the University of Toronto in Toronto, Canada, he moved to New York in 2000 to take up his current positions.

Dr. Rohan is a cancer epidemiologist whose research focuses largely on the etiology, pathogenesis, and prognosis of breast cancer. He has conducted numerous investigations into the roles of molecular, nutritional, and hormonal factors in the etiology of benign breast disease and of breast cancer. He has served on a many site visit and peer review panels, recently completed a term as a permanent member of the National Institutes of Health�s Epidemiology of Cancer Study Section and is currently a member of the NCI Board of Scientific Counselors. Dr. Rohan reviews regularly for many journals, and is an Associate Editor of Cancer Epidemiology, Biomarkers, and Prevention, among other journals. He has published more than 300 articles and book chapters, and has edited two books, one on cervical cancer and the other on cancer precursors.