In normal lung tissues, ADAM17 mRNA levels increased 30.88-fold more than that in ACE2, and in lung cancer tissues, ADAM17 mRNA levels increased 10-fold more than that of ACE2, suggesting that ADAM17 might play a critical role in SARS-Cov-2 entry in cancer patients via lungs, which was supported partially by a systematic review in cancer patients with COVID-19 that lung cancer was more likely to have the risk of COVID-19 when studied the ACE2 expression (43). Here, ACE2 is linked to lung cancer.