Identification and partial characterization of a new pancreatic cancer-related serum glycoprotein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and lectin blotting.

The combination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and peanut agglutinin lectin blotting has been used to identify a pancreatic cancer-related glycoprotein in serum. Its high molecular weight and its lectin-binding characteristics suggest that it probably is a mucin. Comparison with immunoblotting with Ca 19-9 antibody suggests that the epitopes for Ca 19-9 and peanut agglutinin may be variably expressed on different sites of the same mucin. The peanut agglutinin-binding glycoprotein was demonstrated in 12 of 34 pancreatic cancer sera, including four with normal Ca 19-9 assay, and none of 96 control sera, including sera from patients with obstructive jaundice and other cancers. These preliminary results suggest that it may become a useful addition to the current serum markers for pancreatic cancer. The technique of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and lectin blotting may well prove valuable in the search for other cancer-related glycoprotein markers.