TREM2 and neoplasm: By dissecting the DEGs between Mφ_APOE and Mφ_THBS1, we found that both lipid-related genes (APOE, TREM2) and lysosomal genes (GRN, CD63, LAMP1) were highly expressed by Mφ_APOE, and were specifically elevated in the tumor (Fig. 4d, e), indicating lipid-associated and lysosome functions were key identifiers of macrophage in GC (Fig. 4c).