[A study on cathepsin B-like substance in patients with urological cancer]

Cathepsin B is a lysosomal cysteine proteinase which is thought to regulate intracellular protein metabolism. In the present study, cathepsin B-like activity was determined in the urine of 53 patients with renal cell carcinoma, 22 patients with urothelial carcinoma and 41 control subjects. In addition, immunohistochemical study of cathepsin B was performed in specimens obtained from 20 patients with renal cell carcinoma, 59 patients with bladder carcinoma and 20 patients with renal pelvic and ureter carcinoma by using sheep anti-human liver cathepsin B antibody. Cathepsin B-like activity was higher in the urine from patients with renal cell carcinoma or urothelial carcinoma than in that from controls. Positive reactions for cathepsin B were found in 18 of 20 patients with renal cell carcinoma, in 37 of the 59 patients with bladder carcinoma and in 14 of the 20 patients with renal pelvic and ureter carcinoma. In patients with urothelial carcinoma high rates of positive reaction for cathepsin B were observed in patients with advanced stage tumors, with INF gamma-type tumors and with metastatic lesions. In patients with renal cell carcinoma, there was no correlation between the rate of positive reaction and pathological findings. These results indicate that urinary cathepsin B-like activity is higher in patients with urological cancer and that a highly positive reaction for cathepsin B is a risk factor for tumor invasion, metastasis and poor prognosis in patients with urothelial carcinoma.