Increased c-Met tyrosine kinase expression in segmental renal dysplasia

Renal dysplasia (RD) is a disorganized development of renal parenchyma that results in a deficit of functional renal tissue. It has been suggested in the animal model that increased expression of HGF receptor, c-Met tyrosine kinase in the epithelial cells during kidney development may induce a growth of dysplastic epithelia and result in RD. The aim of this study was to investigate the immunoreactivity of c-Met tyrosine kinase in the dysplastic kidney in order to further understand the pathogenesis of RD. Specimens of dysplastic upper pole kidney were obtained from 19 patients during upper pole partial nephrectomy for non-functioning upper moiety of duplex kidney. In the dysplastic kidney, there was strong c-Met immunoreactivity in the epithelium of primitive tubules. In contrast, c-Met immunoreactivity was barely detectable in the normal kidney. Markedly increased expression of HGF receptor, c-Met tyrosine kinase in renal dysplasia suggests that HGF may be involved in the development of renal dysplasia.