TP53 and glioblastoma: Mutation frequencies of DDR genes excluding TERT were rather low in the TCGA glioblastoma data set with only three genes exceeding a predefined 3% mutation frequency in the TCGA glioblastoma data set (STAG [5%], TP53 [53%], ATRX [9%]) all without harboring functional CpGs in their promoter.