Yu et al. (2016) suggested that ACE2 expression is decreased in breast cancer, NSCLC (Feng et al., 2010), hepatocellular carcinoma (Ye et al., 2015), and pancreatic cancer (Zhou et al., 2009), and Zong et al. (2015) reported that ACE2 levels are lower in gallbladder cancer cells than in normal gallbladder cells. Here, ACE2 is linked to breast carcinoma.