TMPRSS2 and lung adenocarcinoma: A clinical TMPRSS2 inhibitor Camostat Mesylate, potently inhibited SARS-CoV and MERS-CoV, also excellently blocked SARS-CoV-2 entry in lung adenocarcinoma cell line Calu-3 at concentrations without obvious toxicity (Hoffmann et al., 2020a).