BRCA1 and breast carcinoma: Importantly, it has been shown that BRCA1 (breast cancer early-onset 1) protein binding to PRC2 inhibits the binding of HOTAIR to the EZH2 component of PRC2, and abolishes HOTAIR-enhanced recruitment of PRC2 to its target HOX (homeobox) A9 gene promoter in human breast cancer cells and fibroblasts [68].