OLIG2 and central nervous system cancer: Using multiplex immunofluorescence (IF) for IL-33, the macrophage/microglial marker Iba1, and h-nucleolin (Fig. 1g), we confirmed that the major cellular source of IL-33 was the human glioma cells (cells positive for h-nucleolin) with a small number of Olig-2 expressing oligodendrocytes in both normal and tumor-bearing animals (Supplementary Fig. 1b).