Decrease in vivo of cysteine endopeptidases in blood of patients with tumor of the larynx

Since cysteine endopeptidase (cathepsins B and L) have been proposed to be implicated in tumor malignancy, we have attempted to decrease these in vivo. Large amounts of urine cysteine peptidase inhibitors (UCPI) are present in the urine of patients. Our results indicate protective effects of a UCIP preparation against human serum cysteine endopeptidases.