E-cadherin Gene Promoter Hyper-methylation in Blood Samples from Breast Cancer Cases

In carcinomas, dissemination of cancer cells via blood or lymph circulation constitutes an early event. E-cadherin is a transmembrane calcium dependent adhesion protein. Cellular de-differentiation and plasticity, underlying metastasis, is attributed to the loss of function of E-cadherin (cdh1) gene. The loss of gene expression may arise from promoter hypermethylation, which has been reported in multiple cancers. In the present pilot project, sixty (60) blood samples were collected from the breast cancer patients at a tertiary care hospital in Karachi, Pakistan. DNA was isolated from the cells circulating in the peripheral blood of the participants. Promoter hypermethylation was investigated through sodium-bisulfite treatment of DNA followed by methylation-specific PCR. In 53.3% of the patients, E-cadherin gene promoter hypermethylation was observed. Promoter hypermethylation of E-cadherin has been reported in DNA isolated from the tissue specimen. However, to the best of our knowledge this is the first report of E-cadherin promoter hypermethylation in cells isolated from the peripheral blood of breast cancer patients from a geographically specific population. The results have important implications in tumour staging and selection of treatment regimens.