A variant of the DNA repair gene XRCC3 and risk of squamous cell carcinoma of the head and neck: A case-control analysis

Individuals differ in their ability to repair DNA damage induced by carcinogens. Studies have shown that polymorphisms in DNA repair genes contribute to individual variation in DNA repair capacity and cancer risk. In a hospital-based case-control study, we tested the hypothesis that a C to T variant (Thr241Met) of DNA repair gene X-ray repair cross-complementing group 3 (XRCC3) is associated with risk of developing squamous cell carcinoma of the head and neck (SCCHN). We genotyped for this variant in 367 non-Hispanic white patients newly diagnosed with SCCHN and 354 frequency-matched cancer-free controls. Compared with the XRCC3 18067CC and 18607CT genotypes, the variant XRCC3 18067TT genotype was associated with a non- statistically significantly increased risk of SCCHN (adjusted odds ratio [ORadj], 1.36; 95% confidence interval [Cl], 0.89-2.08), but this risk was significantly increased among female subjects (ORadj 2.23, 95% Cl, 1.00-4.98) and current smokers (ORadj, 2.26; 95% Cl, 1.02-4.99). These findings suggest that the variant XRCC3 18067TT genotype may not play a major role in the etiology of SCCHN but may contribute to a subset of SCCHN. Larger studies are needed to verify these findings.