Lysosomal enzyme activity in muscle tissue from patients with malignant tumor.

Abstract

The activity of cathepsin D and acid phosphatase of muscle tissue obtained from the abdominal wall in 20 patients with malignant tumor was determined and compared with the corresponding activities in 31 control patients operated on for uncomplicated gallbladder disease or peptic ulcer. Significant increase of the enzyme activities was demonstrated in the tumor patients. No correlation was found between enzyme activity and location of the tumor, grade of tumor cell differentiation, or extension of the tumor. In five patients, additional determinations of enzyme activities were performed at different time intervals after operation, and carried out to cure the disease. In one of these patients, the enzyme activity had increased after 4 months. This patient had lost weight, and metastases were demonstrated at time of this second enzyme determination. In another patient, the enzyme activity had decreased after 20 months. This patient gained weight and revealed no signs of residual tumor or metastases. The results imply that increased activity of hydrolyzing enzymes may be of importance for the development of cachexia in patients with malignancy.