A pilot study on DNA hypermethylation status in promoter region of P16 gene in patients with sporadic breast cancer

Background: Epigenetic modification of cancer-related genes plays a role over and above their genetic alterations and contributes to the tumor initiation and progression of breast cancer. Promoter methylation of tumor suppressor genes is one such epigenetic modification, which can be potential biomarker. In this study, promoter methylation status of p16 gene was studied in blood samples of patients with breast carcinoma.

Methods: Seventy-five patients, freshly diagnosed with carcinoma of breast and 20 age and sex matched healthy control subjects were recruited for the study. DNA extracted from EDTA blood sample was bisulfite converted and subjected to methylation-specific PCR to amplify the p16 promoter region.

Results: Out of 75 patients, 25 (33%) patients showed hypermethylation in promoter region of p16 gene, which was statistically significant in comparison with the control group (p < 0.05). In subgroup analysis, lymph node involvement, cancer grade, and histopathological finding did not show any difference with methylation status of p16 promoter.

Conclusion: Significant hypermethylation of p16 promoter region in the blood of histopathologically proven cases of breast cancer was observed suggesting promoter hypermethylation of p16 may be a possible mechanism accounting for sporadic carcinoma of breast.