MAS1 and breast cancer: As part of the axis formed by ACE2, Ang-(1–7) is an endogenous heptapeptide hormone that mediates biological activity through Mas, whose production has been found to be dysregulated in certain cancers, such as breast cancer (Luo et al., 2015), lung cancer, and prostate cancer (Gallagher and Tallant, 2004; Krishnan et al., 2013a).