TREM2 and hepatocellular carcinoma: There was a significant positive correlation between the expression levels of TREM2 and TGFB1 in TCGA-LIHC and GSE14520 datasets (Fig. 4B, Supplementary Fig. 3A and B), indicating that TGF-β signaling may play a role in inducing TREM2+ macrophages in HCC.