Renal cell carcinoma: immunohistological investigation of expression of the integrin alpha v beta 3.

alpha v beta 3 Integrin has been shown in various tumor entities to promote binding to superficial structures of the basement membrane during metastasis. The goal of the present paper was a structural demonstration of this Integrin in renal cell carcinoma (RCC). After removal of paraffin from formalin-fixed tissue, the cells were labelled with the antibody (VNR 147, H. Biermann, Bad Nauheim) using the peroxidase-antiperoxidase method (DAKO Diagnostical GmbH, Hamburg). Evaluation was carried out microscopically and semiquantitatively from missing (-) through moderate (+) to strong (+2) staining. A total of n = 79 RCCs and n = 53 healthy areas were examined. Semiquantitative staining results: there was a grading-dependent increase (+2) of stainability and thus alpha v beta 3 expression. Two of 53 benign specimens showed strong staining, 11 of 53, only weak staining. Four of 18 G1 RCCs showed strong staining, 11 of 18 only weak staining. Results for G2-RCCs: 11 with strong staining, 21 of 40 with weak staining. G3-RCCs: 4 with strong staining, 2 of 7 with weak staining. Of the metastases, on the other hand, 2 of 14 showed strong staining, another 8 of 14 only weak staining. There were no deviations within the histologic (clear-cell, chromophil, or chromophobe) subpopulations. This grading-dependent expression permits the conclusion that the probability of binding to the human basement membrane mediated by alpha v beta 3 Integrin rises with increasing grading, but the already metastatic cell exhibited this Integrin less strongly, since a basement membrane adhesion is no longer necessary for this cell group.