A study by Wu et al. found this to be true for genes involved in oxidative stress; no single polymorphism affected oral cancer risk, but combinations of polymorphisms in the manganese superoxide dismutase, myeloperoxidase, catalase, and glutathione peroxidase 1 genes were associated with significantly increased risk of oral cancer [52]. The gene discussed is SOD2; the disease is lip and oral cavity carcinoma.