A new technique for simultaneous demonstration of 4 tumor-associated antigens in pancreatic cancer cells.

A new technique is presented for demonstration of 4 tumor-associated antigens in a single slide prepared from paraffin-embedded specimens that can be kept permanently. By sequential processing of the slides with monoclonal antibodies B72.3, DU-PAN-2, CO19-9 and CO17-1A, immunoreactivity with all 4 antibodies can be visualized. Examination of parallel slides stained only with one of the antibodies revealed no interference of the reactive products of the 4 antibodies with each other. Some tumor cells demonstrated reactivity with two antibodies. The described technique provides a possibility to investigate spatial distribution of antigens in tumor cells, and it may be useful for diagnosis, prediction of prognosis and a more appropriate tumor classification.