Immuno affinity purification combined with mass spectrometry detection for the monitoring of VEGF isoforms in patient tumor tissue

Vascular endothelial growth factor (VEGF) is a key mediator of tumor growth and metastasis. At least 7 isoforms of the protein exist due to differential splicing, but little is known about the biological activities of these different isoforms. We purified VEGF from resected human bronchial carcinoma tissue and normal bronchus by immuno affinity chromatography (IAC) and immuno capture (IC) on a ProteinChip® Array, identifying the isoforms by MS. Both methods proved to be useful for the analysis of protein isoforms, which are present in situ in tumor tissue. Different expression patterns of VEGF were demonstrated in tumor tissue compared to healthy tissue. The possibility to analyse VEGF protein isoforms in situ creates new opportunities to study the regulation of angiogenesis in healthy and malignant tissues.