SPP1 and cancer: Although the proangiogenic effect of OPN has been documented under various pathophysiological conditions, including in various cancers,19, 20 the results obtained in the present study show that the exogenous OPN icosamer peptide, OPNpt20, binds to endogenous αvβ3-integrin and induces proangiogenic effects in vitro and in the postischemic brain using mutant peptides and blocking antibodies.