CDKN1A and breast cancer: GEN has been known to block breast cancer cells in G2/M phase of the cell cycle by induction of p21 WAF1/CIP1 expression [39] and increase acetylation of histones 3 and 4 and H3-lysine4 at the p21 WAF1/CIP1 and p16 INK4a transcription start sites, mediated by induction of histone acetyltransferases (HATs) in prostate cancer cells [40].