BPDE-like DNA adduct level in oral tissue may act as a risk biomarker of oral cancer

Abstract

ObjectiveMost reports have shown that PAH-related DNA adducts are positively correlated with the smoking status of oral cancer patients. However, these reports did not focus on a specific carcinogen in cigarette smoke. The purpose of this study was to elucidate the role of the BPDE (7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene)–DNA adduct in the development of oral cancer in Taiwanese patients. DesignWe enrolled 158 oral cancer patients and 64 non-cancer controls to investigate whether there were differences in susceptibility to cigarette smoke exposure in the formation of DNA adducts between cancer patients and controls. Immunohistochemistry and ELISA (enzyme-linked immunosorbent assay) were used to evaluate BPDE–DNA adduct levels in this study. ResultsOur data showed that the BPDE–DNA adduct levels were positively correlated with gender, smoking status, betel nut chewing and alcohol consumption. The difference in DNA adduct levels could be explained by genetic polymorphisms of glutathione S-transferase M1 (GSTM1), but not by cytochrome P-4501A1 (CYP1A1). Patients with high DNA adduct levels (≧34.03 adducts/108 nucleotides) had an approximately 9.936-fold risk of oral cancer compared with those with low DNA adduct levels (<34.03 adducts/108 nucleotides) (p<0.001). ConclusionsWe suggest that genetic background and carcinogen exposure may increase the risk of developing oral cancer.