I am the pathologist for the ovarian cancer section of the "Nurses' Health Study," an epidemiology based investigation of risk factors for disease in women sponsored by NIH. In that capacity, I have helped to collect tissue and evaluate the histology of several hundred cases of ovarian cancer. We are studying genetic polymorphisms, patterns of gene promoter methylation, and protein expression to correlate molecular markers in tumors to dietary and environmental cancer risk factors. I have evaluated the relevance of specific morphometric (histologic) criterion for pre-cancerous lesions of the endometrium called "endometrial intraepithelial neoplasia" (EIN). We have correlated our subjective diagnoses with mutations in the PTEN gene and risk of subsequent evolution to invasive cancer.