Case-control study of oral and oropharyngeal cancer in whites and genetic variation in eight metabolic enzymes

Background. Genetic variation in xenobiotic metabolizing enzymes may explain differing susceptibilities to the cancer causing effects of tobacco and alcohol. Methods. We compared 203 oral squamous cell carcinoma cases and 416 controls for single nucleotide polymorphisms (SNPs) in 8 genes (CYP1A1, CYP2E1, MPO, mEH, GSTM1, GSTT1, GSTP1, and NAT2). Except for NAT2, genotype frequencies were similar in the 2 groups. We classified subjects as fast or slow NAT2 acetylators genotyping 13 NAT2 SNPs. Results. Fast acetylators were overrepresented in cases (53.7%) compared with controls (43.9%; odds ratio (OR) 1.55, 95% confidence interval (CI) 1.08-2.20; p value =.03). Gene-gene interaction testing suggested several cancer-NAT2 associations, with association strongest among persons without a CYP1A1 variant ((star)2C or (star)4) allele (OR 1.77, 95% CI 1.20-2.60, p value = 03) or with a variant MPO (463A) allele (OR 2.38, 95% CI 1.34-4.21, p value =.05). Conclusion, These results implicate fast NAT2 acetylation as a risk factor for oral cancer. (c) 2008 Wiley Periodicals, Inc.