Increased expression of EGFR and TGF-alpha in segmental renal dysplasia in duplex kidney.

Renal dysplasia (RD) is a disorganised development of renal parenchyma that results in a deficit of functional renal tissue. It is known that the epidermal growth factor (EGF) and the transforming growth factor-alpha (TGF-alpha) enhance renal cell proliferation, migration and differentiation during kidney development through binding to the same EGF receptor (EGFR). The aim of the study was to analyse the expression of TGF-alpha and EGFR in the dysplastic kidney. The specimens of dysplastic upper poles duplex kidneys were surgically resected from 19 patients. Indirect immunohistochemistry was performed using the ABC method employing antibodies against EGFR and TGF-alpha, and gene expression using primers specific to the human genes. There was absent or weak EGFR and TGF-alpha immunoreactivity in normal kidney tissue. In dysplastic kidneys, there was strong TGF-alpha and EGFR immunoreactivity in the epithelium of primitive tubules and strong EGFR immunoreactivity in the connective tissue around the primitive tubules. Our findings of markedly increased local expression of EGFR and TGF-alpha in primitive tubules suggest that EGFR and TGF-alpha may play an important role in altering renal morphogenesis resulting in renal dysplasia.