MARCO and breast carcinoma: Relative proportions of cluster 2 were dramatically altered by breast cancer, increasing from being almost non-existent in N to being the most abundant subpopulation of T. Gene set enrichment analysis (GSEA) of cluster 2 showed the highest enrichment scores in MARCO+ macrophages to be lysosome, proteasome, oxidative phosphorylation (OXPHOS) and citrate cycle (TCA cycle) (Figure 2H), consistent with the functions of MARCO in phagocytosis and clearance (37).