WHAT IS CA 72-4 (CARBOHYDRATE ANTIGEN 72-4, CANCER ANTIGEN 72-4, TUMOR-ASSOCIATED GLYCOPROTEIN 72, TAG 72)TEST?
The MUC1 gene is a high-molecular-weight glycoprotein found in specific tissues throughout the body (see Mucin-like carcinoma-associated antigen—Blood). The MUC1 gene has many varieties of carbohydrate chains that are termed mucin-like antigens, and one of these is the carbohydrate antigen 72-4 (CA 72-4) that circulates in the bloodstream when cancer is present. CA 72-4 is elevated in several types of gastrointestinal cancer and in ovarian cancer, and levels are most useful when evaluated in combination with other carbohydrate antigens. CA 72-4 is not helpful in detecting micrometastasis of colorectal cancer but is positive in advanced metastatic tumours. It is being investigated for its usefulness as a prognostic indicator of survival in gastric cancer. CA 72-4 levels are determined using a monoclonal antibody immunoassay.