ANGPT2 and neoplasm: In mouse tumor transplantation studies, exogenous Angpt4 has been reported to either inhibit (Xu et al., 2004) or promote tumor growth (Brunckhorst et al., 2010; Kesler et al., 2015), and similarly to Angpt2, Angpt4 expression has been reported to increase in hypoxia (Abdulmalek et al., 2001).