CD34 and neoplasm: Considering the results of the tumor cell apoptosis experiments, the in vitro destructive effect on the VM channels and in vivo CD34- PAS dual staining experiments, and the anti-angiogenic effect in the reported reference, we suggest that NGR-SSL-CA4 can target U87-MG cells, and the VM formed by U87-MG cells as well as endothelial cells compared with SSL- CA4.