BRCA1 and breast cancer: We knocked down Gata3 in MMTV-PyMT tumor cells that were isolated and screened from MMTV-PyMT mammary tumors and were confirmed as Gata3 and Brca1 proficient (Gata3+/+;Brca1+/+) luminal type before and after transplantation into mammary fat pads (MFPs) of recipient mice (Fig. 2a, and details in [31, 32]).