TREM2 and neoplasm: Emerging functional biomarkers including TREM2, SPP1, SPI1, C1Q, S1P, CXCL9, NUPR1, MS4A4A, Siglec-G/10 and BST2, have been proposed as indicators of immunosuppression, lipid metabolism, phagocytosis, antigen presentation, glycolysis, angiogenesis, hypoxia, and tumor cell invasion in TAMs across various malignancies [85, 279–289].