furin mRNA levels were 49.56-fold higher than that of ACE2 in lung normal tissues and 4-fold higher in lung cancer tissues, implying that SARS-CoV-2 might not only use TMPRSS2 or ACE2 to attack tissues from normal and cancerous organ tissues, but also use furin, particularly in lung cancer tissues. This evidence concerns the gene TMPRSS2 and lung cancer.