A core patient-survival gene network, and its community structure and robustness. This network contains 42 genes, most of which, upon mutated, are significantly correlated with patient survival (based on Cox proportional hazards model). The nodes/genes in the network are found to be naturally organised into seven communities (C1 to 7), each associated with distinct aspects of cancer biology. The significance (P value) of the communities is evaluated by two-sample Wilcoxon tests on two types of node degrees: within-community degrees versus between-community degrees. The thickness of an edge indicates the confidence score (under data removal). The bottom-left inset shows the cumulative distribution of the edge confidence scores.