Serum cathepsin B levels, urinary excretion of cathepsin B and tissue cathepsin B content in the patients with gastric cancer.

Serum cathepsin B levels and urinary excretion of cathepsin B in the patients with gastric cancer were significantly higher than those in the control non-cancer patients. Moreover, cancer tissue cathepsin B content was significantly higher than that in the normal tissue. After radical curative operations for gastric cancers, both serum cathepsin B levels and urinary excretion of cathepsin B were restored to the control values. These results suggest a possible role of lysosomal enzyme, cathepsin B in the pathogenesis of tumor growth, and also suggest that these parameters might be possible indicators for tumor malignancy.