Our results indicated that, while the XRCC1 Arg399Gln and Arg280His polymorphisms may not increase or decrease the risk of HNC, when cigarette smoking and alcohol consumption were taken into account, the XRCC1 Arg194Trp polymorphism was associated with increased risk of HNC and also may modulate genetic susceptibility to oral cancer. This evidence concerns the gene XRCC1 and lip and oral cavity carcinoma.