BRCA1 and breast carcinoma: To investigate whether the levels of HspBP1 expression affect tumorigenesis in breast cancer, we stably depleted HspBP1 in BRCA1-proficient (MCF-7 and MDA-MB-231) and BRCA1-deficient (MDA-MB-436) breast cancer cells using HspBP1-specific shRNAs (Fig. S1A) and stably overexpressed GFP-HspBP1 in each cell line (Fig. S1B).