NRP1 and neoplasm: In accordance, tumor vessel parameters and tumor cell proliferation in GAC were not suppressed with VEGFR2/NRP1 complex formation in trans. These data indicate that the level of NRP1 expression in tumor cells relative to endothelial cells dictates whether trans‐complexes (VEGFR2/NRP1 complexes between endothelial and tumor cells) dominate over cis‐complexes (VEGFR2/NRP1 complexes on endothelial cells).