Normally, a tumor suppressor gene requires a biallelic inactivation, and this unusual TP53 behavior has led to the formulation of two hypotheses: the first contemplates an oncogenic gain of function (GOF) of TP53 missense mutants [46], the second envisages a dominant negative effect (DNE), that leads to a selection for TP53 missense mutations, with a non-mutational impairment of the remaining WT allele [47]. Here, TP53 is linked to neoplasm.