We found that cells with tumor morphology co-expressed TfR1 and GFAP; additionally we observed co-expression of TfR1 and the stem cell-related markers CD133 and nestin, which is consistent with recently reported data demonstrating that GBM cells co-express TfR1 and the stem cell-related marker SOX2 [20]. This evidence concerns the gene PROM1 and neoplasm.