BIOCHEMICAL-IDENTIFICATION OF AN EXTRACELLULAR GLYCOPROTEIN (ECM56) IN HUMAN BRAIN-TUMORS

In malignant Morris hepatoma 7777 of the rat, an extracellular glycopr otein with high molecular weight was identified. In the present study of human brain tumors, we have detected an identical extracellular gly coprotein with a molecular weight of 56 kDa (ECM56) under reducing con ditions, which belongs to the group of high molecular weight glycoprot eins. Fifteen intraoperatively acquired tissue samples of ten glioblas tomas, three astrocytomas WHO grade III, one oligoastrocytoma grade II -III, one ependymoma grade III, and two normal adult brain specimens o btained at autopsy were investigated. In this series, ECM56 could be d etected biochemically in all glioblastomas and ependymomas, but not in astrocytomas and normal adult brain. Immunohistochemically, ECM56 was mainly distributed in tissue areas with vascular proliferation. Thus, ECM56 might be related to malignant neoplastic growth in the brain an d, therefore, may represent a biochemical marker of malignancy.