Expression of nucleotide excision repair genes and the risk for squamous cell carcinoma of the head and neck

BACKGROUND Phenotypic differences in the ability to repair genetic damage induced by tobacco carcinogens may reflect genetic differences in susceptibility to squamous cell carcinoma of the head and neck (SCCHN). The objective of this study was to assess the variation in baseline expression of five nucleotide excision repair genes between individuals with SCCHN and cancer free controls. METHODS The authors conducted a hospital-based case–control study of 57 SCCHN patients and 105 cancer free controls. Using peripheral blood lymphocytes, a multiplex reverse transcriptase–polymerase chain reaction assay was used to quantitate in vitro the mRNA levels of five genes (ERCC1, XPB/ERCC3, XPG/ERCC5, CSB/ERCC6, and XPC) involved in the nucleotide excision repair pathway. RESULTS The levels of ERCC1, XPB/ERCC3, XPG/ERCC5, and CSB/ERCC6 transcripts were lower in cases than in controls (P =0.0001, 0.096, 0.001, and 0.0001, respectively). In multivariate logistic regression analysis (adjusting for age, gender, race, smoking status, and alcohol use), low expression of ERCC1, XPB/ERCC3, XPG/ERCC5, and CSB/ERCC6 was associated with a statistically significant increased risk for SCCHN (adjusted odds ratios [95% confidence intervals] 6.42 [2.63–15.69], 2.86 [1.39–5.90], 3.69 [1.73–7.90], and 2.46 [1.19–5.09], respectively). CONCLUSIONS Reduced expression of ERCC1, XPB/ERCC3, XPG/ERCC5, and CSB/ERCC6 is associated with a more than two-fold increased risk of SCCHN. Cancer 2002;94:393–7. © 2002 American Cancer Society.