Polymorphism of NQO1 (C609T) in Relation to Susceptibility to Oral Squamous Cell Carcinoma

The NQO1 gene, encoding the phase II drug-metabolizing enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1), is regarded as an important enzyme for susceptibility to carcinogenesis in humans. Japanese people show a polymorphism (C609T) in NQO1 as C in the wild-type genotype (wt) and T in the variant genotype (vt). In this study of 105 patients with oral squamous cell carcinoma (OSCC), the wt/wt, wt/vt and vt/vt genotypes were found in 42, 49 and 14 cases, respectively, while each genotype was detected in 49, 52 and 1, respectively, of 102 control cases with no carcinoma at any site in the body. The χ2 test revealed that individuals with the vt/vt genotype were less common in the control cases than in the OSCC patients (P < 0.001) and the odds ratio of the vt/vt to the wt/wt genotype was 16.3. The results indicate that susceptibility to OSCC appears to depend significantly on the NQO1 polymorphism.