Activetargeting of nanoparticles may be a solution for bypassing the organsrich in RES and increasing the efficacy of drug delivery to tumors.33 Decoration with folate is a promising functionalizationfor the nanoparticles since FRs are upregulated to meet the increasedmetabolic demand for folic acid in cancer.30 Under physiological conditions, there were very limited numbersof tissue-resident CD206+ subset of macrophages that werepositive for FRβ. This evidence concerns the gene FOLR2 and cancer.