BRCA1 and breast cancer: Interestingly, recent studies have demonstrated that DNA hypomethylation can cause the redistribution of the H3K27me3 epigenetic marks and derepression of PRC2-targeted genes.33 Conversely, DNA hypomethylation can also be coupled to repressive chromatin domain formation and gene silencing through the deposit of H3K27me3 in breast cancer.29 Our data suggest that FOXA1 gene expression is negatively regulated by EZH2, a key subunit in PRC2, as chemical inhibition or siRNA-mediated depletion of EZH2 enhanced FOXA1 expression in Brca1-knockout MMECs and MCF-7 cells.