A previous global DNA methylation profiling study of a large cohort of brain tumors revealed that TERT mutation was the least specific parameter for GBM compared with EGFR amplification or whole chromosome 7 gain and whole chromosome 10 loss, suggesting that TERT mutation alone may be an insufficient diagnostic marker of GBM.26 Interesting, one of our mGBM patient with TERT mutation alone had prolonged OS after RT without chemotherapy. The gene discussed is EGFR; the disease is brain neoplasm.