Molecular mechanisms of tumor-associated macrophages in hepatocellular carcinoma development and therapy

Table 1 Examples of tumor-associated macrophages subpopulations and their functions in hepatocellular carcinoma

TAM subpopulation	Key markers	Main functions	Mechanisms of action	Ref.
M0 (FCGR1A)	CD86, TNFRSF14, SIGLEC10	Interacting with tumor cells or other immune cells through their ligands or receptors	Ligand/receptor interaction to impact anti-tumor immunity	Ye et al[22]
M1(FCGR1A)	CD86, TNFRSF14, SIGLEC10
M2 (MSR1, CD163, and CD209)	CD86, SIGLEC10, TNFRSF14, LGALS9, HAVCR2, ITGB2
TAMs	C1QA, APOE, C1QB, TREM2, ID3, MITF, RUNX2, MAF	High TAMs were associated with poor prognosis	Expression of SLC40A1 and GPNMB	Zhang et al[7]
Myeloid-derived suppressor cell-like macrophage	THBS1, BCL3, NR4A1, RXRA, TCF25
SPP1+BCL2A1+ TAMs	SPP1 BCL2A1	HCC patients with high SPP1+BCL2A1+ TAM expression further exhibited significantly poorer responses to anti-PD-1 therapy	Suppression of T cell function	Lai et al[23]

TAMs: Tumor-associated macrophages; CD: Cluster of differentiation; SPP1: Secreted phosphoprotein 1; PD-1: Programmed cell death protein 1; HCC: Hepatocellular carcinoma; TREM: Triggering receptor expressed on myeloid cells.