FSTL3 and hepatocellular carcinoma: To further examine the impact of FSTL3 overexpression on M2 macrophage abundance in HCC, we developed a fibroblast–macrophage co-culture model and revealed that FSTL3 overexpression strongly elevated the surface markers of M2 macrophage (CD206 and CD163) in THP-1 macrophages (Fig. 7G–H).