TP53 and neoplasm: A positive role for mutant p53 in maintaining malignancies has also been shown in cell culture systems in vitro (Bossi et al. 2006; Hui et al. 2006) and in vivo, where inactivation of mutant p53 caused tumor shrinkage and improved survival in lymphomas (Alexandrova et al. 2015) and tumor shrinkage in dextran sulphate sodium (DSS)-induced colorectal cancer (Schulz-Heddergott et al. 2018).