A New 180kDa. Urine Protein Marker Associated with Bladder Cancer

Abstract

We surveyed the tumor-related proteins present in the urine specimens of 118 bladder cancer patients to seek a possible marker enabling future diagnosis and prognosis of this disease. We identified a protein of 180 kDa. by sodium dodecyl sulfate polyacrylamide gel electrophoresis in urine samples subjected to prior adsorption by protein-A conjugated to a sepharose bead. This protein appears to be a glycoprotein because it binds to concanavalin A-conjugated sepharose and can be eluted by .alpha.-methyl D-mannoside. It does not react immunochemically with antibodies prepared against either carcinoembryonic antigen or epidermal growth factor receptor, both of which have an apparent molecular weight close to 180 kDa. We found this protein in the urine of 74.3% of the patients with transitional cell carcinoma. It was not present in age-matched controls, patients with benign prostatic hyperplasia or patients with 10 other cancers. There was 1 false positive result in a patient with prostate cancer. It does not appear to be associated with urinary tract infection, blood contamination, premedication or anesthesia.