Isolation and characterization of the glycoprotein (JBB5) in the urine of a patient with carcinoma of the colon.

Patient J. B. with metastatic carcinoma of the colon excreted 0.5 to 1.0 g protein daily, about one-third of which was in Molecular Weight Class 30,000 to 60,000. The major component of this class was isolated by gel filtration and ion-exchange chromatography. The purified protein, labeled JBB5, contained about 11% sialic acid, 8% hexose, and 4% hexosamine. Its molecular weight was between 51,000 and 59,000. It did not react detectably with antisera to any of the recognized normal human plasma proteins. A specific antiserum to JBB5 was raised in the rabbit. Urine from 4% of subjects with nonneoplastic illnesses reacted in double immunodiffusion with anti-JBB5. Thirty-three % positive reactions were obtained with urines from patients with advanced neoplastic disease, the percentage varying from 64% in metastatic cancer of the pancreas to 15% in chronic lymphocytic leukemia.