Genetic Polymorphism of hOGG1 (C1245G) and Risk for Cervical Cancer in Northeast Thais in Association with Oral Contraceptive Pills and Secondary Smoking

Abstract

Background and Objectives: Tobacco smoke and oral contraceptive pills are carcinogens associated with cervical cancer development. These substances produce oxidative damage to the DNA structure resulting in increasing the numerous of 8-oxodeoxyguanine (8-oxodG). Human 8-oxoguanine glycosidase (hOGG1) has a major role for repairing of damaged DNA. The polymorphism of hOGG1 (C1245G) provides 3 genotypes; CC, GG, and CG genotypes. The polymorphism may be associated with cervical cancer development. This study was to investigate the association between cervical cancer risk and hOGG1 polymorphism in combination with oral contraceptive pills and secondary smoking.

Methods: An aged matched case-control study conducted 182 invasive cervical cancer patients and 182 controls. They were asked to answer questionnaire and collected blood samples for DNA extraction. The hOGG1 genotype was analyzed by using real-time polymerase chain reaction (real-time PCR) method. Then, the association between hOGG1 polymorphism and the risk of cervical cancer among northeast Thais, combined with oral contraceptive pills and secondary smoking were analyzed by using logistic regression.

Results: The association between hOGG1 polymorphism and the risk of cervical cancer among northeast Thais was observed. Among secondary smoking and in non-use of oral contraceptive pills, the CG genotype were associated with reduction of cervical cancer development with adjusted OR, 0.38 (95%CI: 0.18-0.81, p = 0.01) and 0.45 (95%CI: 0.22-0.94, p = 0.03), respectively. However, the hOGG1 polymorphism was not increased risk for the cervical cancer in subjects who were  non-smoker partner and in subjects who use contraceptive pills (p>0.05).

Conclusions: Our data suggest that hOGG1 polymorphism is associated with the risk of cervical cancer among secondary smoking and non-oral contraceptive pills. CG genotype of hOGG1 may be substantially reduced risk of cervical cancer of these subjects among northeast Thais.

Keywords: hOGG1, polymorphism, cervical cancer, oral contraceptive pills, secondary smoking