In agreement with their damage protection role, enhanced Ink4/Arf and p53 activity protects mice from cancer (Garcia-Cao et al., 2002; Tyner et al., 2002; Maier et al., 2004; Matheu et al., 2004, 2007, 2009; Mendrysa et al., 2006). This evidence concerns the gene CDKN2A and cancer.