GDF15 and glioblastoma: We subsequently cross‐referenced these proteins against the Cancer Genome Atlas glioblastoma dataset using GlioVis to identify corresponding genes upregulated in human glioblastoma specimens compared to normal brain tissue,[4, 16] finding a critical group of factors (ANG2, GDF‐15, MMP9, OPN, SERPIN E1, UPAR, CD31) upregulated in glioblastoma and generated by engineered perivascular cultures.