Fig. 4

Validation with independent data. GSE16011 data set was used to validate the Lasso-20 signature with respect to impact on survival. The dataset included glioma grades I-IV, and 8 controls. To show the relevance of using all grades, we have included grade III samples in the validation. a Unsupervised expression clustering. b Principal Component Analysis showing the first two components. Each dot represents a sample plotted against expression levels of 20 genes. Samples are colored according to the grade, green being the normal controls. c Cox proportional hazards survival analysis for grades I, II, IV. The model includes age, and grade as covariates, and the 20-gene Prognostic Index