Evaluation of promoter methylation status of MLH1 gene in Iranian patients with colorectal tumors and adenoma polyps.

AIM

The aim of this study was to evaluate the methylation status of the promoter region of MLH1 gene in colorectal cancer (CRC) and its precursor lesions as well as elucidate its association with various clinicopathological characteristics among Iranian population.

BACKGROUND

Epigenetic silencing of mismatch repair genes, such as , by methylation of CpG islands of their promoter region has been proved to be an important mechanism in colorectal carcinogenesis.

METHODS

Fifty colorectal cancer and polyp tissue samples including 13 Primary colorectal tumor and 37 Adenoma polyp samples were enrolled in this study. Methylation-specific polymerase chain reaction (MSP) was performed to find the frequency of MLH1 Promoter Methylation.

RESULTS

Promoter methylation of gene was detected in 5 out of 13 tumor tissues and 4 out of 37 adenoma polyp. The frequency of methylation in tumor samples was significantly higher compared to that in polyp tissues (P= 0.026). No significant association was observed between promoter methylation and clinicopathological characteristics of the patients.

CONCLUSION

The frequency of  promoter methylation in CRC and colon polyp was 18%. Our findings indicated that methylation of promoter region alone cannot be considered as a biomarker for early detection of CRC.