CA 72-4 (CARBOHYDRATE ANTIGEN 72-4, CANCER ANTIGEN 72-4, TUMOUR-ASSOCIATED GLYCOPROTEIN 72, TAG 72) BLOOD TEST
CA 72-4 Can be used in combination with tumour M2-PK for detection of gastric cancer. CA 72-4 is specific (100%) for oesophageal, gastric, and colorectal cancer, but not very sensitive (18%, 32%, and 56%, respectively) when tested alone. When used in combination with M2-PK, there is increased sensitivity for gastric cancer up to 81% and increased sensitivity for oesophageal cancer to 74% (Schneider et al, 2005). The test is more sensitive than CA 125 for ovarian cancer and has been found to be most elevated in the mucinous type of ovarian cancer; it is less sensitive than CA 19 for pancreatic cancer.
The MUC1 gene is a high-molecular-weight glycoprotein found in specific tissues throughout the body. 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 micro-metastasis 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.