KDR and neoplasm: The concentration in the tumor of the 131I-BSA-MSNs-anti-VEGFR2 group at 24 and 72 h post-injection was 32.2 ± 2.8%ID/g and 23.0 ± 1.8%ID/g, respectively, when compared to the non-targeted group (26.1 ± 2.5%ID/g and 12.3 ± 1.2%ID/g, respectively).