BRCA1 and breast carcinoma: To confirm that, we silenced BRCA1/p220 for 24-168h in normal HME cells, MCF7 (estrogen receptor-positive, ER+) or MDAMB231 (ER−) breast cancer cell lines (both express detectable levels of BRCA1/p220 protein, see Figure 1A and 3A, left).