BRCA1 and breast cancer: Moreover, in EZH2, the BRCA1-binding region overlaps with the HOTAIR-binding domain, and BRCA1 inhibits the binding of EZH2 to HOTAIR. Thus, decreased expression of BRCA1 causes genome-wide EZH2 retargeting and elevates H3K27me3 levels at PRC2 target loci, which play a role in HOTAIR-related breast cancers [40], as shown in Figure 2(7).