Novel epitopes on the CA50-carrying antigen: chemical and immunochemical studies

Novel tumour-associated epitopes showing elevated levels in sera from patients with colon carcinoma were studied by means of monoclonal antibodies with respect to co-expression with the tumour-associated epitope CA50 on the cancer antigen (CanAg) glyco-conjugate complex. Co-expression of the different epitopes and CA50 was found on CanAg both from COLO 205 spent medium and sera from patients with colorectal cancer. In a few sera from patients with non-mucinous ovarian tumours, the CanAg complex was also found to express the CA125 epitope. The chemical characterisation showed that all of the novel epitopes on CanAg were of carbohydrate nature, and the results may suggest a structural relationship between several of them.