In contrast, the Caco2 colorectal adenocarcinoma cell line, used in several infection studies of SARS-CoV and SARS-CoV-2 [17], has 0.47-fold lower and 56-fold higher mRNA for ACE2 and TMPRSS2, respectively, compared to wtHEK293 cells. Here, TMPRSS2 is linked to colorectal adenocarcinoma.