For this tumor model primary RCAS-PDGFb tumors were re-transplanted into Cx3cr1GFP/wtCcr2RFP/wt mice, which allowed us to FACS-isolate RFP-/GFP+ microglia and RFP+/GFPlow macrophages/monocytes from tumors, as well as RFP-/GFP+ microglia from control brains and RFP+/GFPlow monocytes from peripheral blood without further antibody staining (Fig. 4B; [23]). The gene discussed is PDGFB; the disease is neoplasm.