CD109 and hepatocellular carcinoma: Recent studies pointed out that downregulation of CD109 with siRNA inhibited cell growth in squamous cell carcinoma (SCC) of the oral cavity,9 and CD109-targeted shRNA knockdown suppressed cell proliferation and induced apoptosis in hepatocellular carcinoma.3 Meanwhile, in our study, we observed that transient knockdown of CD109 suppressed the cell migration, proliferation and self-renewal ability.