Based on our observation that BST-2 inhibits HIV-1 ΔVpu in HepG2 and HeLa cells (Figs S2 and 5a), we found that HBV could promote HIV-1 ΔVpu virus release from BST-2-positive HepG2 hepatoma cells but not from non-hepatic HeLa cells. The gene discussed is BST2; the disease is hepatocellular carcinoma.