| BackgroundColorectal cancer, one of the common malignant tumors, is a major health problem worldwide. It is reported that in worldwide 1.2 million new colorectal cancer cases and 609,000 deaths were expected to occur in 2008. Epidemiologic and biologic studies have suggested that a common feature of colorectal cancer is sex difference, not only in incidence, but also in the development of cancers between male and female. Such gender disparity can be attributed to multi-factors such as life style, habit, and occupation. In addition to these reasons, sex hormone, particularly estrogen, might function as the major regulatory factor. Patients with similar stages and pathologic types have a different progression as well as prognosis between males and females, and cancers can be alleviated or stimulated by altering the accustomed hormonal environment. There have many evidences, most from estrogen replacement treatment (ERT). This study aims to investigate the association between the polymorphisms of ESRs and the risk of colorectal cancer, and provide theoretic base to prevent and treat colorectal cancer.MethodsGenomic DNA was extracted by the whole blood DNA kit from 709 colorectal cancer cases which has two panels and 747 controls. Four SNPs were selected, two of ESR1 XbaI and PvuII, and two of ESR2 RsaI and AluI. PCR-RFLP and Taqman probe methods were used for genotyping. Multivariate logistic regression models were used to investigate associations between allelic, genotype and cancer risk, Odds ratio (OR) and 95% confidence interval (CI) were calculated to show the relative risk. SPSS version 16.0 software was used for all analyses.ResultsIn the colorectal panel I, no statistical differences were detected between the four polymorphisms and colorectal cancer. In the colorectal cancer panel II, allele T of ESR2 RsaI was associated with a significant risk of CRC(OR,1.240; 95%CI, 1.014-1.516; adjusted Pfre, 0.036). For the combined of colorectal cancer panel I and panel II, the P values for the association of ESR2 RsaI and colorectal cancer became much more significant (allelic association, OR, 1.209; 95%CI,1.024-1.426; adjusted Pfre,0.025; additive model, OR, 1.207; 95%CI,1.023-1.424; adjusted Padd,0.025)Conclusion1. The T-C substitution of ESR2 RsaI is common in Chinese people. Polymorphism of ESR2 RsaI T is associated with the increased risk with colorectal cancer in Chinese Han population.2. No association was detected with ESR1 polymorphism and colorectal cancer risk, so it can also indicated that ESR2 may be the dominating receptor in the colorectal cancer. |
