Tumor acidic microenvironment and targeted pH molecular imaging

The tumor acidosis or low extracellular pH (pHe) is a consequence of the anaerobic glycolysis and hypoxia. Tumor acidosis plays a crucial role in tumor progression, metastasis, and resistance to therapy. Recent advances in molecular imaging targeted to tumor acidic microenvironment, including the acido chemical exchange saturation transfer magnetic resonance imaging (AcidoCEST MRI), pH-sensitive nanoparticle and pH-low insertion peptide (pHLIP), offer the opportunity to facilitate the mechanism research in this field and to promote the diagnosis and treatment. This review summarizes the effects of tumor microenvironment on tumor cells and the underlying mechanisms. In addition, this article concentrates more on the application of molecular imaging targeted tumor acidic microenvironment. Key words: Tumor microenvironment; Hydrogen-ion concentration; Molecular imaging; Trends