NRP1 and pancreatic neoplasm: We genetically modified BxPC-3 cells, which were shown to express the highest level of NRP-1 among available pancreatic cancer cell lines (Additional file 1: Figure S1), by transfecting them with an NRP-1 shRNA or a scrambled control (Sc) shRNA vector, generating BxPC-NRPlow or BxPC-Sc cells, respectively.