Breast cancer affects one in eight American women, but its prevalence varies by family, population and ethnic group. Genetic syndromes account for 10-20% of breast cancer and are more common in people with a young onset of breast cancer, a family history of breast cancer, or a tumor that does not express hormone receptors or the tumor marker HER2/neu (triple negative breast cancer; TNBC). Mutations in genes controlling BRCA1/BRCA2 have been found in about 1/4 familial breast cancer patients and at least 13 other genes (Table 1.) whose protein products interact with the BRCA proteins have also been found to segregate with cancer risk in high-risk families. We wish to determine the prevalence of mutations in breast cancer-risk genes in breast cancer patients of Mexican ancestry. We will do this by applying DNA capture and massively parallel sequencing to identify all classes of inherited mutations in 13 breast cancer genes in ELLA study participants (IRB 06-0856-02; Comparative Study of Breast Cancers and their Risk Factors among Mexican Women in Mexico and the United States). Demographic and clinical information, including self-identified race, age of diagnosis, family history, tumor grade and histology, and hormone receptor status will be used to define host and tumor characteristics associated with inherited mutations in each breast cancer gene. In Aim 2, we will develop and pilot a program to return test results to participants, and subsequently to recruit other potentially affected family members. The long-term goal is to identify women who have mutations in specific breast cancer risk genes, which will form the basis of longitudinal studies to estimate penetrance of each gene with regard to the risk of breast and other cancers.
1. To genotype breast cancer risk genes in women of Mexican ancestry who were diagnosed with breast cancer and enrolled in ELLA study.
2. To explore the relationship between carrier status and tumor subtype.