To evaluate the role of constitutive epigenetic changes in normal body cells of BRCA1/BRCA2-mutation negative patients, we have developed a deep bisulfite sequencing assay targeting the promoter regions of 8 tumor suppressor (TS) genes (BRCA1, BRCA2, RAD51C, ATM, PTEN, TP53, MLH1, RB1) and the estrogene receptor gene (ESR1), which plays a role in tumor progression.
These findings provide insight into the mechanism of genomic instability in ERα-positive breast cancer and suggest that individuals with mutations in RAD51C that are exposed to estrogen would be more susceptible to accumulation of DNA damage, leading to cancer progression.