Association between genetic polymorphisms of base excision repair pathway and glioma susceptibility in Chinese children

Glioma is an aggressive malignant primary tumor in the central nervous system[1,2].Although the pathogenesis of glioma is unclear,the only identified environmental risk fac-tor is ionizing radiation[3].However,other factors also may alter the glioma risk,among which gene polymorphisms may play prominent role in glioma susceptibility.Base exci-sion repair(BER)is a DNA repair mechanism that maintains genome integrity and guarantees DNA base modification properly.Many significant and common proteins involved in the BER pathway are associated with cancer.They are poly(ADP-ribose)polymerase 1(PARP1),human 8-oxo-guanine DNA glycosylase(hOGG1),flap endonuclease 1(FEN1),apurinic/apyrimidinic endonuclease 1(APEX1 or APE1),DNA ligase Ⅲ(LIG3),and X-ray repair cross-com-plementing group 1(XRCC1).PARP1 can regulate proteins by poly(ADP-ribosyl)ation and can repair damaged DNA by recruiting and modifying DNA repair complexes.OGG1 gene is composed of six introns and seven exons,encoding HOGG1,which can initiate the BER pathway by hydrolyz-ing the glycosidic bond to produce abasic sites.FEN1 is a critical enzyme of the RAD2 structure-specific nuclease family that displays a variety of endonuclease and exonu-clease activities and provides relevant biological functions.