COL4A1 and glioblastoma: Of the 1,697 genes, 97 genes were cancer genes or cancer candidate genes (Additional files 1); 11 of them were oncogene including CDK4 and RAF4; and 21 of them were tumor suppressor genes including TP53 and RB1. Twenty-five of which were GBM related genes including TCF12, TP53, COL4A1, COL3A1 and COL5A2. We also observed that of the 1,697 genes, 242 genes were in signal transduction pathways, 908 genes were down regulated and 789 genes were up regulated (Additional files 2).