Epigenetic Testing for Breast Cancer Risk Stratification

Promoter region hypermethylation of tumor suppressor genes is one the earliest molecular events in malignant transformation and is readily detectable in apparently normal benign breast epithelium adjacent to breast cancers. We hypothesize that DNA methylation of certain genes occurs as a field change in benign breast tissue that is at high risk for malignant transformation, and as such, can be exploited for tissue-based breast cancer risk stratification. Additional work is required to identify new DNA methylation markers potentially useful for periareolar fine needle aspiration (RP-FNA)-based breast cancer risk stratification, to determine whether these markers are methylated more frequently in benign samples from women who develop breast cancer, to determine whether assessment of these markers is reproducible, to determine whether tamoxifen reduces DNA methylation, and to better understand the pattern of DNA methylation in benign samples from unselected healthy control populations. Each of these objectives contributes to advancement of a clinically useful RP-FNA-based breast cancer risk stratification test. In addition, identification of genes that are preferentially methylated in estrogen receptor (ER) negative breast cancer will provide clues to the underlying biology responsible for this aggressive form of breast cancer. This knowledge may lead to the discovery of the causes of ER negative breast cancer, approaches for recognizing women at increased risk for this type of breast cancer, and approaches for reducing this risk.