Next, macrophages were classified according to their origin (HCC or para-carcinoma tissue), and SLC40A1 expression status (whether they expressed SLC40A1 or not) into four groups: (1) from para-carcinoma tissue and expressing SLC40A1 (N_exp group), (2) from para-carcinoma tissue but not expressing SLC40A1 (N_noexp group), (3) from HCC tissue and expressing SLC40A1 (T_exp group), and (4) from HCC tissue but not expressing SLC40A1 (T_noexp group). Here, SLC40A1 is linked to hepatocellular carcinoma.