Although the importance of numerous genes, including TP53, PTEN, EGFR, MDM2, CDKN2A and CDKN2B (4–6), during glioma progression has been proven, assays for individual genes/proteins or in combination with histological features are neither predictive of survival of glioma patients nor able to guide therapeutic decisions (7). The gene discussed is PTEN; the disease is glioma.