MGMT and central nervous system cancer: Consequently, this could affect (bias) the prediction quality of the methylation status of MGMT for grade II and III glioma by MGMT-STP27, and may explain the higher number of positive calls by MGMT-STP27 when compared to MS-MLPA (specificity of only 0.609 when using MGMT-STP27 as predictor of MS-MLPA methylation calls).