HBx mutants, particularly C-terminal-truncated mutants (ctHBx), are frequently detected in the tumor tissues of HCC patients but are rarely observed in surrounding non-tumor tissues.7, 8 Furthermore, these mutant forms of HBx can also enhance the transformation abilities of ras and myc.9 However, little is known regarding whether or how ctHBx might be involved in carcinogenesis and tumor progression, especially in association with bone morphogenetic protein (BMP) and activin membrane-bound inhibitor (BAMBI)/TGF-β signaling in hepato-carcinogenesis. This evidence concerns the gene TGFB1 and hepatocellular carcinoma.