Tumor perivascular PDGFBR as an independent prognostic factor in metastatic colorectal cancer.

3571 Background: New vessel formation is an essential factor for tumor growth and metastasis. Tumor vessels show reduced and variable pericyte coverage. Several pericyte markers have been identified, including platelet-derived growth factor receptor beta (PDGFbR), smooth muscle α-actin (ASMA) and desmin. Variability in pericyte status and its prognostic significance remains largely uncharacterized in colorectal cancer (CRC). The aim of the present study was to perform a preliminary analysis of the variability in expression of the three pericyte markers and to investigate the potential prognostic significance of perivascular PDGFbR (PV-PDGFbR). Methods: A population-based cohort was used for double-staining, performed on 100 tumors with CD34 and above-named pericyte markers. For the rest of the study a metastatic CRC (mCRC) collection from the phase III NORDIC-VII study was used. Analyses were performed on a tissue microarray with tumor material from 328 out of the 566 patients in the intention to treat po...