CD274 and oral cavity squamous cell carcinoma: STAT3 activation has also beenreported in response to renal cancer exosomes, which engaged TLR2 and enhancedMDSC suppressive functions (89).Distinctly, in a model for oral squamous cell carcinoma, exosomes released byhypoxic tumor cells activated a miR-21/PTEN/PD-L1 axis to engage theimmunosuppressive effects of MDSCs on T cells, an effect that could be blockedby the simultaneous targeting of PD-L1 and miR-2 (90).