The most common histological pattern observed in 16 K14-cre; ApcCKO/+ mammary tumors from mice in the mixed background were acinar (Figure 1E, 2A–E), often associated with basosquamous (Figure 1F, 2F–J) and pilar (Figure 1D, 2K–O) components but only occasionally with undifferentiated component (Figure 1G, 2P–T). This evidence concerns the gene KRT14 and breast cancer.