In each of the tumors in which MMTV activated Sdc2 or Phf19; MMTV also activated Wnt1, Fezf1, Sfmbt2, Ddn, Rspo2, Rspo3 or Fgf3. Similarly Kim et al. [10] have shown that Tcf7l2, Antxr1/Tem8 and Arhgap18 MMTV CIS, which appear at a low frequency, confer on cells altered growth kinetics and morphological transformation in three dimensional culture and occur in mammary tumors having multiple MMTV CIS. The gene discussed is TCF7L2; the disease is breast cancer.