Isolation of glycoprotein antigen from ascites fluid of pancreatic carcinoma

A glycoprotein antigen from the ascites fluid of pancreatic carcinoma has been isolated with the use of perchloric acid extraction and chromatographies on Sepharose 4B, DEAE-Sephadex, and DE52, followed by Sephadex G-200. The purified glycoprotein was found to be homogenous by sodium dodecyl sulfate polyacrylamide gel electrophoresis. A molecular weight of 185,000 dattons was determined by gel filtration. The molecule contained 55% protein and 45% carbohydrate. Both the amino acid and carbohydrate compositions were different from those of carcinoembryonic antigen. This glycoprotein antigen of pancreatic cancer cross-reacted with anticarcinoembryonic antigen; however, the antiserum prepared from this antigen did not react with carcinoembryonic antigen. The biological significance of this glycoprotein in pancreatic cancer is being studied.