SLC40A1 and hepatocellular carcinoma: When co-cultured with human HCC cell lines HepG2 or MHCC97H cells, THP-1 monocyte-derived macrophages upregulated genes involved in iron uptake (ACO1, IREB2, TFRC, and SLC11A2) and downregulated genes involved in iron storage and export (TF, and SLC40A1; Additional file 1: Figure S2B).