OVER-EXPRESSION OF HEPATOCYTE GROWTH-FACTOR IN HUMAN KAPOSIS-SARCOMA

Kaposi's sarcoma is a highly vascularized multifocal tumor which frequ ently appears as a complication of HIV infection. It has been suggeste d that a disorder in the cytokine network may contribute to the develo pment of the disease. We examined the expression of several cytokines in human sporadic Kaposi's-sarcoma specimens, as well as in spindle ce lls cultured from human lesions, and consistently found high levels of expression of hepatocyte growth factor (HGF). In addition, human lesi on-derived spindle cells synthesize and secrete biologically active he patocyte growth factor and express the hepatocyte-growth-factor recept or (c-MET). Moreover, elevated levels of transforming growth factor be ta 1 (TGF beta 1) mRNA were found in lesions of human sporadic Kaposi' s sarcoma and in lesion-derived spindle cells which also over-express urokinase. Since HGF, TGF beta 1 and urokinase are all involved in cap illary-vessel organization, dysregulation of these interacting agents may play a role in the initiation and/or progression of Kaposi's sarco ma, stimulating the growth of spindle cells and recruiting endothelial cells into the lesion. (C) 1996 Wiley-Liss, Inc.