Concordant with their roles in tumor progression [37], the TREM2+ and UBE2C+ TAMs were abundant in PTs compared to NTs and MTs, which was concordant with their prognostic values for predicting poor survival of patients with primary liver tumors rather than metastatic liver tumors (Fig. 5D, E and Additional file 1: Fig. S6E, F). This evidence concerns the gene TREM2 and neoplasm.