CD81 and hepatocellular carcinoma: PLC cells [21], Hep3B cells [22] and HepG2-CD81 cells are hepatoma-derived cells lines which although differ cytologically from one another share similar hepatocytes-like characteristics with Huh7 cells, such as cuboidal epithelial-like morphology with high nucleus-to-cytoplasm ratio, containing mono- and bi-nuclei with multiple nucleoli and cytoplasmic granules (Additional file 1: Figure S2).