PECAM1 and neoplasm: On the one hand, CaO2@mPDA-SH nanoparticles exert antitumor immune responses by stimulating the maturation of DCs and increasing the proportion of M1 macrophages, and thus resulting in tumor growth inhibition; On the other hand, CaO2@mPDA-SH exert its antiangiogenic and anti-metastatic activities through the downregulation of VEGF and CD31 expression.