ANTIGEN HETEROGENEITY IN ADVANCED COLORECTAL AND BREAST-CANCER

The association of several monoclonal antibody defined tumour-associat ed antigens with colorectal and breast carcinoma tissues was investiga ted by immunocytochemistry. The antigens included CEA and the related antigen, NCA (NCA-1), modified blood group substances (Le(y) hapten), a tumour glycolipid antigen and the MUC1 mucin. The molecular expressi on of these antigens in tumour cell membranes was analysed by identifi cation of antigens in detergent extracts by SDS-PAGE analysis and West ern blotting. The capacity of viable tumour tissue to release these an tigens as soluble components into short term tissue culture supernatan ts was further examined. The findings provide a basis for the defining those membrane-associated antigens which would be appropriate targets for monoclonal antibody based targeted therapies in colorectal and br east cancer.