Neuropilin-1 (NRP1) Expession in Tumor Metastasis of Primary and Colorectal Cancer: Implications for Antiangiogenic Therapy

ABSTRACT Introduction and objective Vascular development is critical in tumor biology and targeted therapies against angiogenesis process have proven their therapeutic efficacy. Neuropilin-1 (NPR1), a membrane glycoprotein that works as a receptor for semaphorins, is also a co-receptor for VEGF-A165 and it is expressed in endothelial cells and in many other tumors. Very few studies about this protein in primary and secondary tumors have been reported with contradictory conclusions1,2. The aim of this study is to analyze the relationship between the expression of NRP1 in colorectal cancer patients in primary tumor and metastases and clinical and pathologic features, treatment response, progression-free interval and overall survival. Patients and methods From 1995 to 2010, 70 patients with available biological material in paraffin of primary tumor and metastases (liver and/or lung) have been selected. NRP1 expression was performed using immunohistochemistry with neuropilin-1 Rabbit Monoclonal Antibody Catalog # 2621-1 (ATOM) at 1:75 dilution. Vascular endothelium was used as positive control and tumor sample without antibody as negative control. Clinical and pathological data of patients, treatments administered, toxicity, response, progression-free interval and overall survival were registered. Results The mean age of patients was 63 years. 51 patients (85%) were adenocarcinoma and 46 patients (76%) were moderately differentiated. 34 patients (56.7%) presented metastatic disease at the moment of primary tumor diagnosis. NRP1 expression exists in 100% (120) of samples analyzed. Conclusions In our study, in contrast to latest published data2, no differences about intensity and frequency of expression of NRP1 were found between primary and metastatic samples. It is not possible to establish any relationship between tumor response to treatment and evolution. References: 1. Parikh AA, Fan F, Liu WB, et al. Neuropilin-1 in human colon cancer: expression, regulation, and role in induction of angiogenesis. Am J Pathol 2004;164:2139-51. 2. Jubb AM, Strickland LA, Liu SD, Mak J, Schmidt M, Koeppen H. Neuropilin-1 expression in cancer and development. J Pathol 2012;226:50-60. Disclosure All authors have declared no conflicts of interest.