Abstract: The present invention provides an angiogenesis inhibitor containing as an active ingredient LYPD1 protein or a derivative thereof, a part thereof, or a vector expressing the same, or a cell expressing the same. The present invention also provides a screening method for angiogenesis inhibitors that enhance the expression of LYPD1 protein wherein the method includes (i) a step for treating a first cell by a test substance and culturing and (ii) a step for detecting the expression level of LYPD1 protein from the first cell and comparing with the level of LYPD1 protein of an untreated first cell.

Abstract: Provided is a LYPD1 inhibitor for promoting vascular endothelial network formation in a biological tissue. Also provided is a medicinal composition, said medicinal composition comprising a LYPD1 inhibitor as an active ingredient, for treating and/or preventing neoangiogenic disorders. Also provided is a method which comprises: (a1) a step for providing a cell population containing first cells expressing LYPD1 and vascular endothelial cells; (a2) a step for treating the cell population obtained in step (a1) with a LYPD1 inhibitor; and (a3) a step for culturing the cell population obtained in step (a2).