Jung and colleagues demonstrated detectable GFAP values in 40 of 50 GBM patients’ serum samples (median: 0.18 μg/L; range: 0 to 5.6 μg/L) using ELISA test, when non-GBM tumor patients and all healthy subjects showed zero serum GFAP levels in all samples [17]. The gene discussed is GFAP; the disease is neoplasm.