Kaplan-Meier analysis of GBM patient survival according to predictive gene expression signatures and age alone. A. PN GBM patients vs. non-PN GBM patients. Molecularly categorized GBM patient survival comparison shows PN GBMs survive longer than non-PN GBMs (Pro, Mes, and ProMes). PN GBM patient survival (mean = 2.2 years, median = 1.4 years) vs. non-PN GBM patient survival (mean = 1.2 years, median = 0.9 years). B. GBM patient age difference for survival: younger than age 40 vs. older than age 40. GBM patients younger than age 40 survive longer than GBM patients older than age 40. GBM age < 40 patient survival (mean = 2.1 years, median = 1.3 years) vs. GBM age > 40 patient survival (mean = 1.4 years, median = 0.9 years).