TMPRSS2 and prostate cancer: As a matter of fact, the effects of H2S on SARS-CoV-2 infection are at present completely unknown; only two reports indicate that hydrogen sulfide modulates ACE2 and TMPRSS2 expression in cellular models other than respiratory cells (not representing, therefore, the entry route for Sars-CoV-2), such as endothelial cells (in which ACE2 is up-regulated by NaHS in a murine model of atherosclerosis) and human prostate cancer cell lines (in which TMPRSS2 is down-regulated by H2S exposure) [45,46].