BRCA1 and invasive carcinoma: In 4-month-old control K5Cre;Brca1;p53 double-mutant mice, we observed widespread epithelial hyperplasia (Figure 1A and Supplementary information, Figure S3) as well as low and high-grade mammary intraepithelial neoplasias (MINs) and invasive carcinomas (Figure 1B and 1C).