Growth factors, Cytokines and VEGF in human neoplastic and inflammatory pathologies: Immunohistochemical basis for nuclear medicine studies

Despite the success of antiangiogenic therapy, a large percentage of patients does not benefit from this targeted therapy. Currently, it is impossible to predict which patient will benefit from antiangiogenic therapy. Reasons for treatment failure may be that the target for the drug is not present or that the drug may not reach the target. Tumor cells produce VEGF, which can lead to paracrine effects in the microenvironment. VEGF121 is freely soluble, whereas VEGF165 is secreted, though a significant fraction remains localized to the extracellular matrix, such as VEGF189 and VEGF206. This will most likely lead to locally high VEGF levels. It is currently impossible to evaluate these local VEGF levels . Noninvasive measurement of VEGF in the tumor (IHC, PCR, Western blotting) might give insight to the available target for VEGF-dependent antiangiogenic therapy and thus assist in tumor response prediction. Moreover, growth factors and cytokines expression in normal and pathological tissues substantially changes in different clinical and physiological conditions. These variations (whose different tissue expressions may be effectively studied by immunohistochemistry) are important and constitute the biological basis for a correct tissue analysis. The last one may represent a previous modality screening and a precious therapeutical support in order to ameliorate the knowledge of nuclear medicine targets in oncological patients