TP53 and intraepithelial neoplasia: The accumulation of p53 mutant proteins has been investigated, and frequent p53 gene mutations are likely closely involved in the carcinogenesis of oral squamous cell carcinoma.(Sakai & Tsuchida, 1992) It is generally believed that p53 overexpression is significantly higher in oral leukoplakias that transform into cancer and that epithelial dysplasia is derived from p53‐mutated stem cells (Braakhuis, Leemans, & Brakenhoff, 2004).