SPP1 and neoplasm: Cells in Mac_0 were characterized by expression of complement-related genes (C1qa, C1qb, C1qc) and cytokines (Spp1, Ccl12), while cells in Mac_1 expressed higher levels of several tumor-associated macrophage-related genes such as Arg1, Cebpb, and Ier3 (Fig. 3c).