TP53 and neoplasm: Some authors have considered that the most important ones are genetic susceptibility (for example, mutations in the P53 gene and defects in other genes responsible for DNA repair), advanced age and depressed cell immunity (immunosuppression produced by the first tumor or individual susceptibility).2 Other factors suggested in the literature have been growth factor production from the original tumor and exposure to common inducing agents, such as smoking or predisposition to carcinomas of the head and neck, lung, liver and bladder.