Tumor-Associated Carbohydrate Antigen 19-9 (CA 19-9), a Promising Target for Antibody-Based Detection, Diagnosis, and Immunotherapy of Cancer.

Carbohydrate antigen 19-9 (CA 19-9) also known as sialyl Lewis A is a tetrasaccharide overexpressed on a wide range of cancerous cells. CA 19-9 has been detected at elevated levels in sera of patients with various types of malignancies, most prominently pancreatic ductal adenocarcinoma. After its identification in 1979, multiple studies have highlighted the significant roles of CA 19-9 in cancer progression, including facilitating extravasation and eventually metastases, proliferation of cancer cells, and suppression of the immune system. Therefore, CA 19-9 has been considered an attractive target for cancer diagnosis, prognosis, and therapy. This review discusses the synthesis of CA 19-9 antigen, elicitation of antibodies through vaccination, development of anti-CA 19-9 monoclonal antibodies, and their applications as imaging tracers and therapeutics for a variety of CA 19-9-positive cancer.