Costaining of the panmacrophage marker F4/80 with C3 and the tumor cell marker Olig2 revealed that C3 expression itself was found in areas staining positive for both F4/80+ and Olig2+ cells (Figure 5H), indicating that C3 expression can conceivably come from both these cell types in murine GBM. The gene discussed is OLIG2; the disease is glioblastoma.