Using RNA velocity, recent scRNAseq studies revealed that a TAM population with an embryonic signature in human liver cancer, characterized by high expression of HES1, FOLR2, CD163 and CD206 was at least partially derived from tissue resident macrophages, while other TAM subsets (TREM2+ TAMs and IL-4I1+ TAMs) were identified to be monocyte-derived. This evidence concerns the gene TREM2 and liver cancer.