Initial studies had already shown that BMP-9 binds specific receptors in the HCC cell line HepG2 [28], and further data indicated that these cells express ALK2, BMPRII, ActRIIA and ActRIIB [27,29,30], presenting all the components required for BMP-9 signaling. The gene discussed is ACVR2A; the disease is hepatocellular carcinoma.