ARG1 and central nervous system cancer: Tumor microarrays of glioma (n = 88), colon cancer (n = 23), breast cancer (n = 62) and lung cancer (n = 24) samples were used to identify B cells (anti-CD20), CD4+ T cells (anti-CD4), CD8+ T cells (anti-CD8), regulatory T cells (Tregs, anti-Foxp3), macrophages (anti-CD68) and myeloid-derived suppressor cells (MDSCs, anti-Arginase-1) by multiplex immunohistochemistry (mIHC) (Fig. 1a and Supplementary Fig. 1a–d).