APOE and intrahepatic cholangiocarcinoma: Clusters 1, 5 and 9 are mainly from ICC tissue, which expressed a number of tumor-promoting genes, such as VEGFA (40), MMP14 (41, 42), MMP19 (43), S100A2 (44), APOE (45), HMOX1 (46), SLAMF7 (47), SIRPα (25, 48), LAG-3 (49), and IL-18 (50).