Among them are the long known mutations in p14ARF[118], overexpression of MDM2 [119], amplification of MDM4 in melanoma[120], elevated expression and the anti-apoptotic role of p53-related protein p63 [121], and increased expression of iASPP [122] -all of which act to inhibit the function of p53. Here, PPP1R13L is linked to melanoma.