Satumomab, also known as B72.3, is a modified mouse monoclonal antibody which could specifically bind to tumor-associated glycoprotein (TAG-72). This antibody was developed by Cytogen Corporation, which was acquired by EUSA Pharma in 2008. Satumomab is usually combined with some radioactive elements to diagnose colorectal cancer and ovarian cancer. Satumomab is also used to study the distribution of tumor cell-associated antigens in breast cancer. The original satumomab monoclonal antibody was produced by purifying the membrane enrichment part of human breast cancer biopsy tissue and immunizing mice. In fact, in addition to colorectal and ovarian cancer, satumomab can also interact with a variety of cancer cells, including gastric cancer, pancreatic cancer, endometrial cancer and lung adenocarcinoma. For a variety of normal adult tissues, except secretory endometrium, B72.3 had no effect or only weak response. However，Cytogen Corporation discontinues selling satumomab in 2002.
The characteristic that satumomab can bind to tumor antigen TAG-72 has been used in the clinical study of various cancer detection. Serological tests used satumomab showed that 50% of cancer patients could be detected TAG-72 and 4% of the control population could be detected TAG-72. Satumomab is also used to detect embryonic carcinoma and fine needle biopsy in human effusion and as a diagnostic tool to distinguish lung adenocarcinoma from non-small cell lung cancer or malignant mesothelioma. Labeled satumomab-assisted computer scanning is used to study the localization of tumor lesions. The target of satumomab, TAG-72, is a kind of tumor marker with high specificity and few false positive. Because TAG-72 widely exists in all kinds of cancer tissues and has little expression in normal and benign lesions, anti-TAG-72 monoclonal antibody, which uses satumomab as substitute, has been applied to the study of immunohistochemistry and immunocytochemistry. Those monoclonal antibodies have become a useful tool for clinical tumor diagnosis and differential diagnosis.
Fig.1 Mechanism of action of Satumomab