<；P>；PROBLEM TO BE SOLVED: To provide a neovascularization inhibitor in which mechanism of neovascularization is clarified further, which is based on new mechanism, and is useful for treating tumor. <；P>；SOLUTION: YB-1 specifically develops in a tumor neogenesis blood vessel, and contributes to the growth factor dependence-proliferation of a vascular endothelial cell. Therefore, expression of YB-1 is inhibited, whereby proliferation of a vascular endothelial cell is controlled, and neovascularization can be inhibited. Since YB-1 specifically develops in a vascular endothelial cell of a tumor neogenesis blood vessel, when expression of YB-1 is inhibited, proliferation of a vascular endothelial cell of a tumor neogenesis blood vessel (namely neovascularization in a tumor tissue) can be inhibited selectively. Moreover, since YB-1 involves drug tolerance or proliferation of a tumor cell, expression of YB-1 is inhibited, it becomes possible to inhibit proliferation of both a tumor cell and a vascular endothelial cell of a tumor neogenesis blood vessel. <；P>；COPYRIGHT: (C)2011,JPO&INPIT
