Study of dna methylation in the promoter region of p15 and e-cadherin genes from head & neck tumours

Background: Hypermethylation of promoter regions of tumour suppressor genes is known to cause downregulation of tumour suppressor genes. We evaluated DNA methylation of two tumour suppressor genes p15 & E cadherin on histopathologically proven cases of head and neck cancers. Objectives: To study Methylation in the promoter region of p15 and E Cadherin genes from tissue samples of head & neck cancer and compare it with peripheral blood. Methodology: Forty three cases of head & neck cancer were taken as study subjects. DNA was extracted from HPE proven head & neck cancers. This DNA was bisulphite modified. Methylation Specific PCR was done on the modified DNA to detect methylation pattern. DNA was extracted from peripheral blood of the same patients and the same procedure was followed on the modified DNA to compare the methylation patterns in head & neck cancer tissue as well as in the blood. Results: DNA methylation was detected in 49% tissue samples and 40% peripheral blood samples in p15 gene & 63% tissue samples and 44% peripheral blood samples in E cadherin gene. Kappa coefficient is 0.346 for p15 gene and 0.277 for E cadherin. Conclusion: DNA methylation of promoter region of E cadherin & p15 tumour suppressor genes which causes them to become downregulated may be one of the mechanisms of development of head & neck cancer. This is a reversible mechanism. Demethylating agents like Azacytidine and Decitabine can be exhibited to patients of Head & neck carcinoma who show evidence of DNA methylation.