TMPRSS2 and COVID-19: Comparisons between furin and TMPRSS2 in different tumor tissues were conducted in TCGA normal datasets, and results are shown in Figure 7A. From Figure 7A, we disclosed that the furin expression is higher than that of TMPRSS2 in most of tumor tissues, except in PRAD, demonstrating that furin might facilitate tumorigenesis and COVID-19 viral entry in most types of cancers.