Expression level of NRP1 and SMAD2 in correlation to mutational status of ras (BRAF) in pancreatic cancer

Abstract

Background: Pancreatic cancer is the second leading cause of death in tumor diseases worldwide. There are more than 300 thousands of newly diagnosed patients and majority of them die eventually. In the pathogenesis, several genes play important role. These include oncogenes, tumor suppressor genes and its related proteins of signal pathways of VEGF and EGFR with a RAS domain. It appears that the gene neuropilin NRP-1 coding for one of the two neuropilins, that bind many ligands, affect cell survival and migration ability. Methods: Retrospective study is based on analysis of 50 FFPE bioptical samples (40 resections, 8 punctures, 2 thin-needle biopsies); histology verified all as adenocarcinomas. The expression level of NRP1 and SMAD2 is measured by IHC by mice monoclonal antibodies Anti-Neuropilin 1 and Anti-SMAD2 (Abcan) on the device BenchMark ULTRA (Ventana Medical Systems), Roche. DNA isolation is executed by QIAamp® DNA Mini Kit. We used Codon Specific Mutation Detection Kit (Diatech pharmacogenetics) for detection of somatic point mutations in codons 12, 13, 61 and 146 of KRAS and NRAS genes. BRAF mutational status was revealed by direct sequencing on ABI Prism 3130. We monitor the level of expression of NRP1 and SMAD2 and correlate it to the mutational status of RAS and BRAF, and disease prognosis. Conclusion: We assume that causal relationship exists between inactive NRP1 and wild-type KRAS, and that these should cause decrease of the rate of tumor growth. These characteristics, which are achievable simultaneously during the histological verification, may serve as a potential prognostic marker for subsequent decision of how radical surgical resection should be. Acknowledgement This work was supported by the research programme of Charles University PROGRES Q28 (Oncology) and the research programme AZV 17-30138A.