ACE2 and hepatocellular carcinoma: Several studies have revealed that ACE2 intervenes in the progression and metastasis of tumors via inhibiting tumor cell proliferation, invasion, migration, and angiogenesis through the ACE2/Ang 1–7/MasR axis (Xu et al., 2017; de Paula et al., 2020); this has been demonstrated in hepatocellular carcinoma (Liu et al., 2015; Mao et al., 2018), prostate cancer (Krishnan et al., 2013a, b; Dominska et al., 2018), nasopharyngeal cancer (Pei et al., 2016; Lin et al., 2018), and head and neck cancer (Hinsley et al., 2017).