Detection of Promoter Hypermethylation of GSTP1 and CDH1 Genes and the Relationship of Histopathological Parameters of the Breast

Background: Breast cancer is the most common cancer in women. Histopathology plays an important part in determining the treatment strategy for women with breast cancer. GSTP1 plays an important role in protecting cells from cytotoxic and carcinogenic agents and it is expressed in normal tissues at variable levels in different cell types. CDH1 plays a critical role for establishment and maintenance of polarity and differentiation of epithelium during the development period. Also, it plays an important role in signal transduction, differentiation, gene expression, cellmotility and inflammations. Methods: In this study the promoter methylation levels of GSTP1 and CDH1 gene which are associated with breast cancer were investigated by technique of Methylation Sensitive High Resolution Melting Analysis (MS-HRM). We analysed primary tumor core biopsies from 80 high-risk primary breast cancer patients (tumors ≥ 2 cm and/or lymphatic metastase and/or distant metastases and/or under 40 years). Also the patients’ histopathologic types were associated with the methylation levels. Results: In our study the promoter hypermethylation status was observed at different rates; GSTP1 and CDH1 hypermethylation frequencies were 82% and 95% respectively. The promoter hypermethylation levels of the genes were found to be significant with lymph node positivity, ER positivity and HER2/neu negativity. Conclusion: Our study is important as being the first study that analyzes association between histopathologic type and GSTP1 and CDH1 gene promotor methylation status in Turkish population.