The Correlation Research Between MGMT Protein Expression In Glioma And MGMT Gene Promoter Methylation Of Cerebrospinal Fluid

ObjectiveWe analyzed methylation of gene O-6-methylguanine-DNA Methyltransferase(MGMT) gene promoter methylation of cerebrospinal fluid from patients by methylation-specific PCR(MSP) and detected MGMT protein expression of glioma tissue by immunohistochemical technique.We discussed the correlation between MGMT gene promoter methylation of cerebrospinal fluid and MGMT protein expression in glioma tissue.In order to find a index that can react glioma MGMT protein expression indirectly.And we may provide more theoretical basis of individual chemotherapy for patients with malignant glioma.MethodsCerebrospinal fluid collected in patients with suspected malignant glioma of the preoperative diagnosis in the tumor hospital of Yunnan Province during March2011to July2012.Medical record reports of these patients and clinical characteristics were reviewed.Cerebrospinal fluid was screened of postoperative pathological diagnosis in malignant glioma patients.Cerebrospinal fluid DNA was isolated by the DNA Extraction Kit(DNeasy(?) Blood&Tissue69504).After the existence of human genomic DNA has been verified, using technology of MSPdetected MGMT gene promoter methylation of cerebrospinal fluid.The cerebrospinal fluid specimens from10cases of patients with cerebral infarction were used as control group for the cerebrospinal fluid specimens of patients with malignant glioma.Results are detected by statistical correlation analysis.Results1. Cerebrospinal fluid DNA of55cases was isolated.Human genomic DNA of55cases was existent and detected by MSP technique.The group of patients with glioma was45cases and the group of patients with cerebral infarction was10cases. 2.The patients with glioma group of29cases were MGMT gene promoter methylation.The methylation rate was64.4%.3.The patients with glioma group of24cases MGMT gene promoter methylation of cerebrospinal fluid. The methylation rate was53.3%.4.By Spearman correlation analysis (P<0.05),there is a positive correlation between MGMT protein expression in glioma and MGMT gene promoter methylation of cerebrospinal fluid.5.The MGMT gene protein expression rate of the male patients with glioma group was66.7%, the female patients was61.9%.6. The MGMT gene protein expression rate of the patients under65years of age with glioma was65.4%. The MGMT gene protein expression rate of the patients over65years of age with glioma was63.2%.7.Byx2test, there is no correlation between the MGMT gene protein expression rate of the patients with glioma and gender,age.8. The MGMT gene promoter methylation expression rate of cerebrospinal fluid of the male patients with glioma group was54.2%, the female patients was52.4%.9. The MGMT gene promoter methylation expression rate of cerebrospinal fluid of the patients under65years of age with glioma was52.6%. The MGMT gene promoter methylation expression rate of cerebrospinal fluid of the patients over65years of age with glioma was50.0%.10. Byx2test, there is no correlation between the MGMT gene promoter methylation expression rate of cerebrospinal fluid of the patients with glioma and gender,age.11. The group of patients with cerebral infarction was non-detected MGMT gene promoter methylation. By Fisher’s exact,there are significant differences in MGMT gene promoter methylation between the group of patients with cerebral infarction and the group of patients with glioma.Conclusions1.It is reliable method to isolate cerebrospinal fluid DNA by the kit method(DNeasy(?) Blood&Tissue69504).2.It could be a minimally invasive method to early screen malignant glioma patients by MSP detecting MGMT gene promoter methylation of cerebrospinal fluid. Its sensitivity and specificity should be a large sample of clinical trials.3.It is expected to become a new way of minimally invasive diagnosing glioma and high risk population by MSP detecting MGMT gene promoter methylation of cerebrospinal fluid.Individual chemotherapy of glioma patients is provided a theoretical basis for the formulation4.There is a positive correlation between MGMT protein expression in glioma and MGMT gene promoter methylation of cerebrospinal fluid.5. There is no correlation between the MGMT gene protein expression rate of the patients with glioma and gender,age.6. There is no correlation between the MGMT gene promoter methylation expression rate of cerebrospinal fluid of the patients with glioma and gender,age.