The investigation of the association between gastrointestinal adenocarcinomas and some dna repair genes

Mutagens, spontaneously released by endogenous and exogenous sources may contribute to development of gastric and colorectal cancers. The oxidant-antioxidant balance is thought to be important in the initiation and promotion of cancer. Major antioxidant molecule serum albumin; in combination with nitric oxide make the effort to prevent the mutagenicity of oxidative stress. Helicobacter pylori (H pylori) may share carcinogenic effect by stimulating the release of reactive oxygen species from the inflammatory cells. The repairing enzymes 8-hydroxy guanine glycosylase-1 (OGG1), Kseroderma pigmentozum C and D (XPC, XPD) restore the eventual oxidative damages in DNA. The aim of this study was to investigate the contribution of OGG1 Ser326Cys, XPC Lys939Gln and XPD Lys751Gln polymorphisms, oxidative stress and H pylori seropositivity to gastric and colorectal carcinogenesis.All eligible, 106 gastric and 110 colorectal carcinoma patients and 116 cancer-free subjects were enrolled in this study. The enzyme polymorphisms were detected by PCR-RFLP. ELISA was done for H pylori IgG serology. Also total antioxidant capacity (TAS), serum nitric oxide and albumin concentrations were measured.The enzymes polymorphisms did not associated with gastric and colorectal cancers. TAS was not a unifying factor determining oxidative stress in all cases, thus, albumin concentrations significantly decreased in cancerous patients. A significant decrease was observed in nitric oxide levels of gastric cancer patients having XPC Lys/Gln and Gln/Gln genotypes. A significant increase in risk of colorectal cancer was found in H pylori seropositive cases. These results highlighted a complex interplay between genetic and environmental factors in the genesis of gastric and colorectal cancers.