BRCA1 and breast cancer: Therefore, it is not surprising that tumorigenic subpopulations in mammary carcinomas induced by different oncogenes, driven by different promoters or induced by loss of tumor suppressors in mammary epithelial cells are differing in their profiles of cell surface markers: e.g. the Sca1+ subset in BALB-neuT mice [37], the CD29HCD24H subset in p53-null mammary tumors [30] and in mammary tumors from BRCA1 conditional knockout mice [35], and the CD61+ subset in MMTV-Wnt-1 mice [36].