DRD1 agonists were proven to exert a major anti-tumor effect in several preclinical models (56, 57).D1-like receptor agonists can potently inhibit the suppressive function of MDSC (203).Paliperidone, a DRD2 antagonist, is reported to inhibit GBM growth and decrease the expression of programmed death-ligand 1(PD-L1) in GBM (205). Here, DRD2 is linked to glioblastoma.