We modeled the levels GFAP, floating all the other measured protein levels and find that we can get a very good estimate of GFAP levels in the 16 GBM, but not the astrocytic group of glioma, using three parameters, HiF-1α, Sp1 and Sp3, all of which are positive, Supplementary Figure 2. Here, SP1 is linked to glioblastoma.