Abstract: Objective To explore the methylation status and expression of hMLH1 and MGMT in glioma, and the role of them in the glioma oncogenesis. Methods Methylation status of the MGMT and hMLH1 promoter regions was assayed in 78 glioma tissues by methylation-specific PCR(MSP). The expression of MGMT and hMLH1 in the glioma was investigated by immunohistochemical technique using monoclonal antibody. Results Methylation in the MGMT and hMLH1 promoter regions was found in 43(55.1%) and 32(41.0%) cases respectively. The median of expression rates of MGMT and hMLH1 in tumor cells were 15.9% and 84.6% respectively. Methylation status in the promoter region showed no obvious correlation with the percentage of expression in tumor cells, and the sex, age, and pathological type. Conclusion As proteins of DNA repair system, the expression of MGMT is much lower than that of hMLH1, suggesting that a number of different pathways may exist in gliomas which is associated with disturbances of DNA repair system.

Key words: glioma, MGMT, hMLH1, immunohistochemistry, methylation-specific PCR