Wif - 1 Breast Cancer Gene Methylation Status Analysis And Polymorphism In The Promoter Region Of The Study

Objective:To investigate the promoter methylation status of WIF-1 gene in breast cancer and the relationship between the single nucleotide polymorphism of WIF-1 gene promoter rs58172684 A/G and rs2336433 C/T site and the development of sporadic breast cancer.Methods:RT-PCR and sensitive methylation-specific-PCR(MSP)were used to detect the mRNA expression and the promoter methylation status of WIF-1 gene in breast cancer and tumor adjacent tissues and benign breast disease. Human breast cancer cell line MCF-7 was treated with either different concentrations of 5-Aza-CdR or different concentrations of TSA. The growth of MCF-7 cells was observed by MTT assay. The expression of WIF-1 mRNA was observed by RT-PCR before and after 5-Aza-CdR and/or TSA. Allele specific amplification (ASA) was used to analyze the single nucleotide polymorphism of WIF-1 gene promoter rs58172684 A/G and rs2336433 C/T site.Results:Significant differences of the mRNA expression were observed among three tissues. Methylation of WIF-1 genesin breast cancer increased significantly compared with tumor adjacent tissues and benign breast disease tissues (χ2=16.484, P<0.05); 5-Aza-CdR and TSA can inhibit the growth of MCF-7 cell line, which was time and dose dependent. After treated with 5-Aza-CdR and/or TSA, the expression of WIF-1 mRNA in MCF-7 was increased. The frequency of WIF-1 gene promoter genotypes rs58172684 A/G and rs2336433 C/T in sporadic breast cancer patients were significantly different from those in the healthy individuals. The frequency of allele gene G of WIF-1 gene promoter rs58172684 site was significantly higher than that of normal controls. The frequency of allele containing genotypes had no significant correlation with the age, clinical stage, histological grades in sporadic breast cancer patients, as well as increased numbers of lymph node metastasis.Conclusion:The promoter methylation status of WIF-1 gene was significantly related with the occurrence of breast carcinoma.5-Aza-CdR and TSA could recover its expression, thereby inhibiting the growth of tumor cells. The single nucleotide polymorphism of WIF-1 gene promoter might play a role in the development of sporadic breast cancer, and G allele may be a genetic risk factor of sporadic breast cancer.