Transgenic mice that carry the PIK3CA-H1047R mutation in the Rosa 26 locus express the PI3Ka mutation in mammary epithelial cells when CRE expression is under the control of the MMTV promoter and develop adenosquamous carcinoma or adenomyoepithelioma (120, 121). The gene discussed is PIK3CA; the disease is adenosquamous carcinoma.