MRC1 and central nervous system cancer: PTEN knockdown was further proved in this study to promote the polarization of M2 macrophages, which is consistent with the findings reported by Bao et al. that PTEN downregulation enhanced expression of M2 macrophage-specific markers (CD206, CD204, CD163), which thus promoted macrophage M2 polarization in glioma (Bao and Li, 2019).