Compared to normal brain tissues, the mRNA level of SOX2, MYC, NOTCH1, STAT3, BMP2, ACVR1, ITGB1, WNT5A, CXCR4 and ZP3 increased significantly in both GBM and LGG as well as the mRNA levels of LIF, PRDM1, IFITM3 and GDF15 increased significantly in GBM but not in LGG (Additional file 1: Fig. S3). Here, GDF15 is linked to glioblastoma.