CYP1A1, CYP2E1, GSTM1, GSTT1, EPHX1 exons 3 and 4, and NAT2 polymorphisms, smoking, consumption of alcohol and fruit and vegetables and risk of head and neck cancer

Purpose As risk-modiWers of alcohol and tobacco eVects,\r\nmetabolic genes polymorphisms were investigated as susceptibility\r\ncandidates for squamous cell carcinoma of the\r\nhead and neck (SCCHN).\r\nMethods A total of 210 cases and 245 hospital controls,\r\nage and gender matched, were genotyped for CYP1A1,\r\nCYP2E1, GSTM1, GSTT1, EPHX1 exons 3 and 4, and\r\nNAT2 polymorphisms. A measurement of the biological\r\ninteraction among two risk factors was estimated by the\r\nattributable proportion (AP) due to interaction and its 95%\r\nconWdence interval (CI).\r\nResults SCCHN risk was associated with high-levels of\r\nalcohol intake [OR = 3.50 (95%CI: 1.93 6.35) and OR = 6.47\r\n(95%CI: 2.92 14.35) for 19 30 g/day and >30 g/day, respectively],\r\ncigarette smoking [OR = 3.47 (95%CI: 1.88 6.41)\r\nand OR = 7.65 (95%CI: 4.20 13.90) for 1 25 and >25 packyears\r\nof smoking, respectively] and low-fruit and vegetables\r\nconsumption (OR = 2.45; 95%CI: 1.53 3.92). No diVerences\r\nwere observed for the genotypes or haplotypes distributions\r\namong cases and controls, and no biological interaction\r\nemerged from gene gene and gene environment interaction\r\nanalyses. An attributable proportion (AP) due to biological\r\ninteraction of 0.65 (95%CI: 0.40 0.90) was detected for\r\nheavy drinkers with a low intake of fruit and vegetables, and\r\nan AP of 0.40 (95%CI: 0.10 0.72) resulted forever smokers\r\nwith low fruit and vegetables consumption.\r\nConclusions Even in presence of high alcohol consumption\r\nor cigarette smoking, a high intake of fruit and vegetables\r\nmight prevent the development of around one quarter\r\nof SCCHN cases. The lack of interaction between the studied\r\npolymorphisms and the environmental exposures suggests\r\nthat chronic consumption of tobacco and alcohol\r\noverwhelm enzyme defences, irrespective of genotype.