Expression of transforming growth factor β in renal cell carcinoma and matched non-involved renal tissue

TGFβ1 is one of several cytokines produced by proximal tubular and renal cancer cells. Previous studies have been mainly focused on determining plasma or serum TGFβ levels, its effect on RCC cultures, and the expression of TGFβ mRNA. Cancerous and autologous normal kidney samples were obtained from 24 patients treated by radical nephrectomy. TGFβ1 expression was determined using a semi quantitative Western blot analysis and immunohistochemistry. Blot densities and immunohistochemical expression intensities in normal and neoplastic tissue were compared, and subsequently correlated to tumor stage, histological type and nuclear grade. All tissue samples examined expressed TGFβ1; mean tumor to non-involved kidney spot density ratio correlated with advancing stage and higher nuclear grade. The overexpression of TGFβ1 in certain RCCs may partially explain their resistance to the growth suppression action of TGFβ. The correlation with tumor stage and grade indicates a possible role in the development of metastatic potential as well as in host’s immune response modulation.