These agents have as the most relevant side-effects, although infrequently, increased bleeding and perforation of the colon.15 A major inhibitor of angiogenesis is the suppressor gene TP53. This gene stops cell cycle progression in nonviable conditions by inducing hypoxia-mediated apoptosis.7TP53 is mutated in 50% of all cancers, including colorectal cancer. The gene discussed is TP53; the disease is cancer.