Renal cysts as preneoplastic lesions of renal cancer. The role of heptocyte growth factor.

J. Kovacs, E. Szabo, A. Varga a, S. Gomba

Department of Pathology and Department of Urology a, University of Debrecen medical and Health Science Center, Debrecen, Hungary

Aim: Hepatocyte growth factor/scatter factor (HGF) actively participates in normal renal development, renal homeostasis and cystogenesis. Besides it regulates cell proliferation and dissociation of cells both of which are involved in tumor growth and metastasis formation. Authors studied the expression of HGF and its receptor, c-MET to find a possible link between the mechanism of cyst development and renal neoplasia. Methods: Surgical and autopsy specimen from inherited and acquired cysts were applied to immunohistochemical methods, in situ hybridisation and Western blotting using anti human HGF and anti human c-MET antibodies and their cDNA probes labeled with digoxigenin. Results: c-MET and HGF was expressed in the epithelium of renal cysts and cystic renal tumors. The intensity of staining showed a reverse correlation to the size of the cysts. Western blotting demonstrated a more concentrated protein within the renal tumors especially in the solid masses. Conclusion: Higher protein synthesis and expression of c-MET and HGF in solid renal tumors highlights its less differentiated status with a higher grade compared to their cystic counterparts. HGF probably plays role in the initiating of the non neoplastic cysts, inducing cell proliferation and cell detachment with secondary obstruction. However the cystic cells may loose their c-MET receptors or inactivates as their presence disappear with cyst expansion.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Diagnostic Markers.