Functional Variants of the NEIL1 and NEIL2 Genes and Risk and Progression of Squamous Cell Carcinoma of the Oral Cavity and Oropharynx

Abstract

Human DNA glycosylases NEIL1 and NEIL2 participate in oxidized base excision repair and protect cells from DNA damage. NEIL1 (MIM:608844) and NEIL2 (MIM:608933) variants may affect their protein functions, leading to altered cell death and carcinogenesis. To date, only one reported study has investigated the association between NEIL1 and NEIL2 polymorphisms and cancer risk. Genotype and haplotypes of the NEIL1 NT_010194.16:g.46434077G>T (rs7182283) and g.46438282C>G (rs4462560) and NEIL2 NT_077531.3:g.4102971C>G (rs804270) polymorphisms were determined for 872 patients with newly diagnosed squamous cell carcinomas of the oral cavity and oropharynx (SCCOOP) and 1,044 cancer-free non-Hispanic white control subjects frequency-matched by age and sex. Crude and adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using multivariate logistic regression, and false-positive report probabilities were also calculated. We found no overall differences in the frequencies of alleles, genotypes, and haplotypes of NEIL1 g.46434077G>T and NEIL1 g.46438282C>G polymorphisms between cases and controls. However, the NEIL2 g.4102971CC genotype was associated with a significantly increased risk of SCCOOP (adjusted OR, 1.30; 95% CI, 1.02-1.65); this increase in risk was the highest among current alcohol drinkers (adjusted OR, 1.87; 95% CI, 1.28-2.72), particularly in patients with oropharyngeal cancer (adjusted OR, 1.35; 95% CI, 1.04-1.76). The NEIL2 g.4102971CC genotype was also significantly associated with SCCOOP of advanced stages. Polymorphisms of the NEIL2 gene may be markers for risk and progression of SCCOOP, particularly in patients with oropharyngeal cancer. Larger studies are needed to confirm our findings.