Application of MGMT Promoter Methylation of Cerebrospinal Fluid in Diagnosis of Glioma

Objective To compare the sensitivity and specificity of O⁶-methylguanine-DNA methyltransferase(MGMT) promoter methylation between peripheral blood and cerebrospinal fluid in the initial diagnosis of glioma patients.

Methods We collected the tumor tissues, preoperative blood plasma and cerebrospinal fluid from 283 patients with glioma admitted by neurosurgery. Contused brain tissues of 10 patients with craniocerebral trauma, and the corresponding blood plasma and cerebrospinal fluid were collected for the negative control. Methylation status of MGMT promoter was determined by methylation-specific PCR(MSP). The methylation rate of MGMT promoter was compared among tumor tissues, preoperative blood plasma and cerebrospinal fluid.

Results The methylation rates of glioma tissues, the corresponding peripheral blood and cerebrospinal fluid promoters were 67.14%, 44.87% and 66.08%, respectively, and 0 in the negative control group. The positive rates of MGMT promoter methylation in different grades of gliomas were 68.13% (WHO Ⅱ), 65.69% (WHO Ⅲ) and 67.78% (WHO Ⅳ), respectively (P > 0.05). In the glioma tissues with positive MGMT promoter methylation, the sensitivity of MGMT promoter methylation in cerebrospinal fluid was 79.66% (141/177), higher than that in blood plasma (58.82%(110/187)) (P < 0.05).

Conclusion The methylation rates of MGMT promoter in tumor tissues, cerebrospinal fluid and peripheral blood are independent of tumor grade. Compared with peripheral blood, the methylation of MGMT promoter in cerebrospinal fluid is more specific and sensitive.