SPP1 and neoplasm: Given the important functions of MMP‐13, ‐14, and ‐2, and of osteopontin in tumor angiogenesis (Basile et al, 2007; Kudo et al, 2012; Kale et al, 2014), we analyzed the area and the size of the blood vessels, but did not find significant changes in activin‐overexpressing mice (Fig 5J and K, and data not shown).