CDKN2A and cancer: Among other causes [95], p16 overexpression in cancer cells has been related to RB1 loss of function [74, 75], which prevents the CDKN2A locus silencing by Polycomb Repressor Complexes [96, 97] and trimethylation of lysine 27 on histone H3 by EZH2 [98, 99].