Interaction of polymorphism with methylation in cervical cancer.

We aimed to investigate the roles and interaction effects of high-risk human papillomavirus (HR-HPV) infection, methyltetrahydrofolate reductase polymorphism, and paired box gene 1 () methylation in cervical intraepithelial neoplasia (CIN) and cervical cancer. Polymerase chain reaction was used to detect polymorphism and methylation; Mantel-Haenszel and Spearman's rank correlation tests were used to analyze the trends and correlations. Forty cases each of normal control (NC), CIN I, and CIN II/III and 9 squamous cell carcinoma (SCC) cases were enrolled. Increase in age increases the risk of cervical cancer. The HR-HPV infection rate, mutation rate, and methylation rate in CIN I, CIN II/III, and SCC groups were significantly higher than those in the NC group ( < 0.05). The above-mentioned rates gradually increased with the degree of cervical lesions. Moreover, HR-HPV infection, polymorphism, and methylation increased the risk of both CIN and cancer. A positive additive interaction was observed between methylation and polymorphism across different cervical lesion groups, whereas no interaction was found between HR-HPV infection and methylation in lesion progression.