Vinculin: Its Possible Use as a Marker of Normal Collecting Ducts and Renal Neoplasms with Collecting Duct System Phenotype

Vinculin is a cytoskeletal protein associated with membrane actin-filament-attachment sites of cell-cell and cell-matrix adherens-type junctions. In this article, we examine the expression of vinculin to elucidate its role in human renal neoplasms. We reviewed surgically resected specimens and selected available tissue from 79 renal tumors in 78 patients. There were 55 men and 23 women. Their mean age was 61 years and the mean size of the renal tumors was 6.1 cm. All renal tumors were examined by immunohistochemistry using a monoclonal antibody against vinculin. Overall, 17 (21.5%) renal tumor samples reacted with vinculin. The positive ratio in various types of renal tumors was as follows: conventional-type (clear cell), 0/54; papillary-type, 5/12; chromophobe-type, 5/5; sarcomatoid-type, 3/4; collecting duct carcinoma, 3/3; and oncocytoma, 1/1. The positive rate of conventional-type renal cell carcinomas (RCCs) is significantly different from that of other renal tumors (P < .01). Normal kidney, conventional, and papillary-type RCCs exhibited positive signals in Western blot analysis. These results suggest that vinculin may serve as a useful marker of renal neoplasms with collecting duct system phenotype such as chromophobe-type RCC.