XPD/ERCC2 EXON 8 polymorphisms: Rarity and lack of significance in risk of squamous cell carcinoma of the head and neck

Background. Inherited polymorphisms of DNA repair genes may contribute to genetic susceptibility to squamous cell carcinoma of the head and neck (SCCHN). The objective was to assess whether two polymorphisms in the nucleotide excision repair gene XPD (ERCC2) are markers of SCCHN risk. Methods. We performed a hospital-based case-control study of 180 SCCHN patients and 400 cancer-free controls frequency matched on age, sex, smoking, and alcohol use. All subjects were non-Hispanic whites. XPD alleles 23047 and 23051 were assessed by digestion with the restriction enzymes XhoII and SphI after PCR amplification. Results. The XPD 23047 G and XPD 23051 T alleles were extremely rare among both the cases and controls (allele frequencies<1.0%), and not statistically different between groups (P>0.6). Conclusions. The 23047 and 23051 variants of the DNA repair gene XPD are extremely rare and do not contribute significantly to the risk of SCCHN in the non-Hispanic white population.