In particular, the overexpression of  Oct4 causes murine epithelial cell dysplasia [25],the aberrant expression of  Sox2  causes the development of serrated polypsand mucinous colon carcinomas [26], breast tumors arecharacterized by elevated expression of  Klf4  [27]  ,  and the improper expression of  c–Myc is observed in 70% of human cancers [28].Tumor development is oberved in ~50% of murine chimeras obtained through the injection ofretroviral iPSCs into blastocysts, which is very likely associated with thereactivation of exogenous  c–Myc  [29, 30]. This evidence concerns the gene KLF4 and cancer.