BMP6 and hepatocellular carcinoma: Even though several other BMPs, including BMP2, 4, 5, 7 and 9, all robustly induce hepcidin expression in primary hepatocytes or hepatoma cell lines [38], [39], and their mRNAs are also detected predominantly in the NPCs of rat liver [16], they cannot compensate the function of BMP6 in Bmp6-/- mice [8], [9].