MC5R and glioblastoma: Most notably, a recent single-cell RNA sequencing study has defined nine myeloid clusters (MC) in human gliomas (including low-grade glioma, newly diagnosed GBMs, and recurrent GBMs), and identified those that were correlated with better survival (e.g., MC2 and MC7, microglia clusters proposed to be anti-tumorigenic) or worse survival (e.g., MC3 and MC5, macrophage clusters proposed to be immunosuppressive and pro-tumorigenic) in GBM patients [24].