An anticancer therapy using autologous cells or the like, which induces the regression of cancer or has favorable drug delivery effects and brings about reduction or withdrawal of a hypoxic region(s) in tumor is provided. Transplantation of endothelial progenitor cells, via intravenously or other methods leads to tumor growth inhibition, an increase of the vascular density with an enlargement of the vascular diameter, and reduction of a hypoxic region(s) in the tumor. Allogeneic transplantation of endothelial progenitor cells may be achieved to secure the cells for the therapy, however, autologous transplantation of endothelial progenitor cells from cancer patients would be desirable to evade rejection. When autologous cells are used, mononuclear cells are separated from the peripheral blood or bone marrow of the patient and cultured using an endothelial differentiation medium containing cytokines such as VEGF to obtain adherent cells, which can then be collected and used as endothelial progenitor cells.