To date, several murine genetic models have been developed to assess the effects of both loss- and gain-of-function Tp53 mutations in cancer (Donehower et al., 1992; Harvey et al., 1993; Jacks et al., 1994; Lang et al., 2004; Lavigueur et al., 1989; Lee et al., 1994; Olive et al., 2004). This evidence concerns the gene TP53 and cancer.