PECAM1 and neoplasm: The observed growth inhibition after pulsatile high dose scheduling seems to occur irrespective of angiogenesis inhibition, as denoted by the lack of inhibitory effect on tumor microvessel density (MVD; number of CD31+ vessels per 40x field: 24 (range: 13-39) vs 27 (range: 16-53) vs 21 (range 17-24) for the vehicle vs daily sunitinib vs weekly sunitinib group, respectively) (Fig. 4a, b).