There is also increasing evidence that the RAAS system may be implicated in cancer. ACE2 was found to inhibit cancer cell growth, metastasis, and angiogenesis in breast (Yu et al., 2016; Zhang Q. et al., 2019), pancreatic (Zhou et al., 2011), and colon cancer (Bernardi et al., 2012). Another study pointed out that hepatocellular carcinoma patients with higher levels of ACE2 had longer survival times, suggesting a positive link between ACE2 expression and better prognosis (Ye et al., 2015). Studies on human xenografts in mice clearly indicated that ACE2 inhibited tumor growth by suppressing invasion and angiogenesis in Non-Small Cell Lung Cancer (NSCLC). Remarkably, the same group demonstrated that overexpression of ACE2 promotes the expression of E-cadherin at expenses of mesenchymal markers such as vimentin, and thereby inhibits the epithelial-mesenchymal transition in NSCLC models (Feng et al., 2010; Qian et al., 2013).