Angiogenesis, tumor cell proliferation, and migration are the hallmarks of solid tumors, such as gliomas. This study demonstrates that a fragment derived from the autocatalytic digestion of matrix metalloproteinase (MMP)-2, called PEX, acts simultaneously as an inhibitor of glioma angiogenesis, cell proliferation, and migration. PEX is detected in the cultured medium of various human glioma, endothelial, breast, and prostate carcinoma cell lines. PEX is purified from the medium of glioma cell lines by chromatography, where PEX is constitutively expressed as a free and a TIMP-2-bound form. In human glioma tissue, PEX expression correlates with histological subtype and grade and with alpha v beta 3 integrin expression to which it is bound. Systemic administration of PEX to s.c. and intracranial human glioma xenografts results in a 99% suppression of tumor growth with no signs of toxicity. Thus, PEX is a very promising candidate for the treatment of human malignant gliomas.