Background: Tumor microenvironment is so complex that involves in many factors
of tumor. Although enhanced permeability and retention effect is a main driving force of tumor
targeted nanoparticles, the tumor microenvironment greatly affects the delivery efficiency of
Methods: A careful search of the scientific database was performed to find the tumor microenvironment
related papers. Then the papers were concluded and reviewed.
Results: In tumor, elevated interstitial fluid pressure, abnormal tumor vasculature, dense tumor
extracellular matrix and elevated solid stress considerably hinder the extravasation and intratumor
penetration of nanoparticles. Therefore, shaping the tumor microenvironment could improve
nanoparticle delivery, including vascular normalization, vasculature promotion therapy, lymph
normalization, reducing tumor stroma components, elevating blood pressure, elevating receptor
expression, cell cycle arrest and priming by cytotoxic therapy.
Conclusion: Shaping the tumor microenvironment could considerably enhance the nanoparticles delivery.