IGFBP3 and glioblastoma: Meanwhile, among the top 10 of the M2 TAM-associated factors identified from the microarray analysis, the heparin-binding factor PTN, but not adrenomedullin (ADM), COL14A1 or IGFBP3, was most consistently upregulated (fold change >6.0) in M2 TAMs relative to the control TAMs in all tested GBM specimens (Fig. 1c,d and Supplementary Fig. 1c–e).