ARG1 and glioblastoma: Furthermore, PSB 0788 also blocked the induction of Arg1 expression by the spent media of MTAP-null GBM cells (Supplementary Fig. S5D), and attenuated other MTA-stimulated M2 marker genes, including Vegfa, Timp1, and IL10, while countering the inhibitory effect of MTA on Mrc1 expression (Fig. 3D–F; Supplementary Fig. S5B)46,48.