TP53 and neoplasm: More than half of p53 mutations are missense mutations in the core domain, especially in several “mutational hotspots,” including arginine-to-histidine substitution at codon 175 (R175H).2 Missense p53 mutation imparts gain-of-function properties, including the inability to control cell proliferation, suppression of apoptosis, and development of chemotherapy resistance,2 which result in tumor progression.