p53, as a tumor suppressor, transcriptionally regulates a lot of target genes that are implicated in various biological processes including DNA damage repair (i.e., GADD45α, PCNA), cell cycle arrest (i.e., CDKN1A), senescence, and apoptosis (i.e., Puma, Noxa, Bax, Bid, Casp1, 6 and 10) [18]. The gene discussed is TP53; the disease is neoplasm.