Anti-epithelial membrane antigen monoclonal antibodies and radioimmunolocalization of colorectal cancer

Abstract

The monoclonal antibodies LICR-LON M8 and 77-1, which react with epithelial membrane antigen, showed a strong reaction with colorectal cancer on immunohistochemistry. In a radioimmunolocalization study in patients with colorectal cancer, 111In-labelled M8 detected 13 of 16 tumour sites present in 16 patients. 111In-labelled 77-1 detected 10 of 15 tumour sites present in 14 patients. The high radioactive background in the liver prevented the detection of hepatic metastases in eight patients (five in the M8 and three in the 77-1 group). The mean (s.d.) tumour to normal colon ratio was 2.5(1.2) for M8 and 1.6(0.5) for 77-1 at day 6 after antibody administration. The mean (s.d.) tumour to blood ratio was 4.9(3.7) for M8 and 3.6(1.5) for 77-1. There was no statistical difference between these results. All scan-positive cancers reacted with M8 and 77-1 on immunohistochemistry. The results suggest that these monoclonal antibodies may have a role in the immunolocalization of colorectal cancer.

Radioimmunolocalisation in breast cancer using the gene product of c-erbB2 as the target antigen

“…This tumour specificity is itself an essential prerequisite to any future development of immunotherapeutic applications (Bradwell et al, 1985;Schlom, 1989). Most previously reported studies have used a single monoclonal antibody of moderate specificity for a tumour to investigate the potential for staging all cases of that cancer type under investigation (Thompson et al, 1984;Yiu et al, 1991), without making allowance for heterogeneity of antigen expression either between different tumour deposits or within a tumour itself. In addition, the level of antigen expression in many tumours is not signficantly elevated above that found on normal tissues, thus making successful tumour localisation unlikely.…”