It is of interest that, although the incidence is low, both H- and K-Ras activation mutations were found in K14-cre; ApcCKO/+ mammary tumors, since K-Ras mutations were frequently found in Myc-induced mammary tumors but not H-Ras and vice versa in MMTV-Wnt1 tumors. This evidence concerns the gene WNT1 and breast cancer.