In this study we investigated the presence of lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) on renal cell cancer in 16 patients who underwent nephrectomy. In all cases, normal renal tissues presented ICAM-1 on the parietal epithelial cells lining Bowman's capsule while neither the visceral epithelium nor the glomerular endothelium were stained. The epithelial proximal and distal tubular cells were stained poorly (5 +/- 3 positive tubular cross sections/mm(2)). No renal cells were stained by the monoclonal antibody for LFA-1. In contrast, in renal cancer tissue we found 6 cases negative for ICAM-1 and the others positive with a mean number of positive tubular cross sections of 52 +/- 37/mm(2). In 10 cases staining with LFA-1 antibody was negative, while for the other cases the mean number of positive tubular cross sections was 11 +/- 8/mm(2). Our results suggest that the expression of ICAM-1 and LFA-1 on the surface of malignant cells may explain the unusual clinical aspects of renal cell carcinoma, its association with the immune system, and clarify certain aspects of immunotherapy.