COL18A1 and glioma: Other activated upstream regulators include: TGM2 (transglutaminase 2), which is associated with glioma stem-like cells [37]; the PAF1 transcriptional complex [38]; IL27, which induces differentiation of glioma cell to astrocytes [39] and promotes anti-tumor immune responses [40] (Additional file 2: Figures S2B and S2C); growth hormone, which increases NK cell cytotoxicity to glioma cells [41]; and the endostatin precursor COL18A1.