TMPRSS2 and COVID-19: Given this, I hypothesised that some of the perturbagens in the L1000 library would have caused a reduction in expression of TMPRSS2 mRNA in the tested human lung cancer cell line, and furthermore, some of the identified perturbagens might be drugs with prior approvals for use in humans, meaning that they could plausibly be repurposed for use as sole or adjunctive antiviral therapies for COVID-19 after further in vitro and in vivo evaluation.