However, interestingly, Molyneux et al. (79) demonstrated that deletion of BRCA1 in mammary luminal epithelial cells—targeted by Blg—can generate basal-like breast tumors, phenocopying the human BRCA1-associated breast cancers, while the deficiency of BRCA1 in basal cells– targeted by CK14– can only generate the malignant adenomyoepitheliomas which are rare in human BRCA1-associated breast cancer. The gene discussed is BRCA1; the disease is breast cancer.