COL4A1 and glioblastoma: By comparing the expression level in different histological types of gliomas (Figure 3B; Table 3), COL4A1 and COL4A2 were better predictors of glioblastoma (AUC = 0.918 and 0.9), followed by COL4A3 and COL4A4 (AUC = 0.67 and 0.746).