PRKAR1A and central nervous system cancer: also revealed that exosomal miR-29a and miR-92a, which were transferred from hypoxia-induced glioma cells to MDSCs could facilitate the formation of the immunosuppressive microenvironment by increasing the proliferation of functional MDSCs via silencing high-mobility group box transcription factor1 (Hbp1) and protein kinase cAMP-dependent type I regulatory subunit alpha (Prkar1a), separately (48).