TP53 and head and neck squamous cell carcinoma: Recently, five case–control studies have been conducted to investigate an association between the p53 codon 72 polymorphism and the risk of squamous cell carcinoma of the head and neck (SCCHN), but none of them have found a positive association (Hamel et al, 2000; McWilliams et al, 2000; Summersgill et al, 2000; Shen et al, 2002; Mitra et al, 2003).