Effect of Promoter Hypermethylation of DNA Repair Gene O~6-methylguanine DNA Methyltransferase to the Treatment of Temozolomide in Glioblastoma

Objective: To investigate the effect of the hypermethylation of MGMT promoter on the treatment of temozolomide to glioblastomas(GBM).Methods: Tumors were chosen(divided into two groups according to different clinical endings with the same treatment of temozolomide);Methylation-specific PCR was used to detect the promoter methylation of the MGMT gene and loss of transcription in glioma tissues.MGMT expression was examined by immunohistochemistry method.Results: The majority(72.2%) of tumors' MGMT protein expressed positive in the group whose clinical endings are bad,but the positive rate is only 39.1% in the other group whose clinical endings are relatively good.Among the 41 GBM samples,MGMT expressed in 22 samples,in which hypermethylation was in 7(31.7%) cases,while there was no MGMT expression in 19 samples,in which hypermethylation was detected in 14(73.7%) cases.Spearman correlation coefficient was used to analyze the result.The relation was significant(P0.05).Conclusion: The relationship between the aberrant methylation of MGMT gene promoter and the expression of MGMT in glioma is significant.The promoter hypermethylation of MGMT can elevate the sensitive of temozolomide through inhibiting the expression of MGMT gene.