Reports have revealed that ACE2 may have both positive and negative roles in cancer therapies, and it has been identified as an inhibitor of cancer cell growth, metastasis, and angiogenesis in lung cancer (Feng et al., 2010), breast cancer (Yu et al., 2016), colon cancer (Bernardi et al., 2012), and pancreatic cancer (Zhou et al., 2011). Here, ACE2 is linked to lung cancer.