PIGF and neoplasm: PEGylated chitosan-based nanoparticles coated with mannose residues and containing anti-VEGF and anti-PIGF siRNAs were efficiently targeted and provided simultaneous downregulation of VEGF and PIGF, which resulted in the remodeling of the tumor microenvironment with an enhancement of the antitumor immune response and, as a consequence, decreased tumor growth and decreased incidence of lung metastases formation.