GFAP and glioblastoma: In GBM tissue, OATP1A2 had a strong positive correlation with GFAP (r = 0.8584, P < .00001) and PDGFRβ (r = 0.8341, P < .00001), and a moderate positive correlation with IBA1 (r = 0.5590, P = .0056), indicating OATP1A2 expression by astrocytes, PDGFRβ + stromal cells and myeloid cells, respectively.