Ender et al. (2014) discovered that the knockdown of Mas expression mediated by small interfering RNA leads to increased cell proliferation in osteosarcoma and suggested that targeting the ACE2/Ang-(1–7)/Mas axis may be beneficial for the treatment of osteosarcoma by reducing cancer cell proliferation and preventing cancer metastasis (Figure 2). The gene discussed is ACE2; the disease is cancer.