ACE2 and hepatocellular carcinoma: To this aim we used different cell culture systems with permissiveness to SARS-CoV-2, the African green monkey kidney cell line VeroE6, the human hepatoma cell line Huh7.5 and the human lung cancer cell line A549 consitutively expressing human angiotensin converting enzyme 2 (ACE2) acting as SARS-CoV-2 entry receptor.