The purification procedure for human gastric juice FSA and its chemical composition

A purification procedure for a gastric cancer-associated glycoprotein FSA is described. This substance was considered to be sulphated but is now found to derive its charge from carboxylic groups and has been renamed foetal sialoglycoprotein. The chemical composition is similar to blood group substances with differences which may reflect its origin from gastric cancer. The molecular size differs from that of the carcinoembryonic antigen. The calculation of the yield based on dry weight measurements is not possible until a radioimmunoassay technique becomes available and development of such an assay is now in progress in our laboratory.