EXPRESSION OF PDGF AND PDGF RECEPTORS IN HUMAN ASTROCYTOMA OPERATION SPECIMENS SUPPORTS THE EXISTENCE OF AN AUTOCRINE LOOP

Established cell lines derived from human malignant astrocytomas typic ally express a combination of platelet-derived growth factor (PDGF) an d PDGF receptor which could form an autocrine loop. In this study, we screened for the essential components of a PDGF autocrine loop in fres h surgical isolates of human astrocytomas, using in situ hybridization and immunohistochemical techniques. Eight malignant astrocytomas (6 g lioblastomas and 2 anaplastic astrocytomas), 5 low-grade astrocytomas and 4 non-neoplastic glial specimens (mesial temporal sclerosis) were evaluated. Malignant astrocytomas, and to a lesser extent low-grade as trocytomas, expressed more PDGF-A and PDGF-B than non-neoplastic glia. PDGF-a-receptor expression was elevated both in malignant and in low- grade astrocytomas. These data support the argument that PDGF autocrin e loops contribute to the unregulated growth of human astrocytomas. Ex pression of PDGF and PDGF receptor in low-grade astrocytomas suggests that activation of PDGF autocrine loops may be an early event in the p athogenesis of malignant astrocytomas. (C) 1995 Wiley-Liss, Inc.