Kaplan-Meier analysis of grade III and grade IV glioma patients stratified either by (A) PC1 scores from real-time PCR data or by (B) histopathological diagnosis. Horizontal axis, month after diagnosis; vertical axis, progression-free survival probability. Blue lines, poor prognosis group (n = 20) (A) or grade IV (n = 26) (B); red lines, good prognosis group (n = 16) (A) or grade III (n = 10) (B). Log rank p-values were 0.023 (PC1 score) and 0.137 (histopathology). Dotted lines indicate 95% confidence intervals.