PTEN and neoplasm: The TP53 gene is a tumor suppressor engaged in cellular death, cellular reprogramming, the remodeling of chromatin, and drug resistance [32]; therefore, alterations to the TP53 gene lead to an escalation of DNA mutagenesis by the inactivation of other tumor suppressor genes, such as the RB1 gene, which controls cell cycle and genomic stability, and the PTEN gene, which regulates PI3K/AKT/mTOR signaling.