TFAP2A and breast carcinoma: Furthermore, studies based on siRNA against AP-2α in MDA-MB-231 cells have shown that the use of 5-aza-2′-deoxycytidine alone for breast cancer treatment does not increase cell apoptosis or cancer sensitivity to chemotherapy; however, proper expression of TFAP2A combined with chemotherapy resulted in loss of tumorigenesis, reduction in colony formation, and heightened chemosensitivity [110].