NRP1 and neoplasm: Here, we hypothesized that linc-OIP5 may regulate the angiogenesis of endothelial cells at a tumor microenvironment and mainly investigated that whether linc-OIP5 in breast cancer cells affects the angiogenesis of human umbilical vein endothelial cells (HUVECs) and whether this regulation is involved in angiogenesis-related YAP1/Notch/NRP1 signaling circuit.