TREM2 and hepatocellular carcinoma: Knockdown of TREM2 can reduce the polarization of M2 phenotype, causing TAMs to remodel into the M1 type, which exhibits a pro-inflammatory and immunostimulatory state, inhibits the growth as well as invasiveness of hepatic cell carcinoma (HCC) (30) and glioma cells (21), and suppresses tumor progression.