CA 72-4 (Carbohydrate Antigen 72-4 or Tumor-Associated Glycoprotein 72) is a blood protein used primarily as a tumor marker.
CA 72-4 also known as TAG-72 (tumor-associated glycoprotein 72), is a high-molecular-weight mucin-like glycoprotein used as a serum tumor marker.
It is a marker to monitor gastrointestinal and ovarian cancers, especially stomach (gastric) cancer.
What CA 72-4 is used for:
Monitoring Treatment: Doctors use it to check how well a patient is responding to chemotherapy or surgery for stomach or ovarian cancer.
Detecting Recurrence: Rising levels can be an early sign that cancer has returned or progressed after treatment.
Combinatory Testing: It is rarely used alone; doctors often measure it alongside other markers like CEA, CA 19-9, or CA 125 to improve accuracy.
Not for Screening: It is not effective or recommended for routine cancer screening in healthy, asymptomatic people.
False Positives Happen: Non-cancerous (benign) conditions can also raise CA 72-4 levels, including: Inflammation or ulcers in the stomach Pneumonia Liver cirrhosis or pancreatitis Gout Ovarian cysts
It is most useful for monitoring gastric cancer—for assessing treatment response, detecting recurrence, and providing prognostic information.
Levels often correlate with tumor stage, burden, and peritoneal dissemination.
Sensitivity is modest (roughly 30–50% overall; higher in advanced stages), but specificity is relatively high (often >90–95% in the context of known gastric cancer).
It is also employed as an adjunctive marker in: Mucinous ovarian carcinomas and is sometimes more useful than CA-125 in these subtypes.
Other gastrointestinal adenocarcinomas (colorectal, pancreatic, esophageal) and occasionally other adenocarcinomas.
Typical upper reference limit is < 6.9 U/mL (some assays use cutoffs around 4–6 U/mL).
Values are method- and laboratory-dependent; always interpreted against the specific assay’s reference interval.
Not suitable for screening or primary diagnosis due to limited sensitivity and the possibility of elevation in benign conditions (e.g., pancreatitis, cirrhosis, benign ovarian disease, inflammatory GI disorders).
Best used serially in patients with an established diagnosis of a relevant malignancy, often in combination with other markers (CEA, CA 19-9, CA-125).
Elevated levels do not confirm cancer; declining levels after treatment support response, while rising levels may signal recurrence or progression preceding clinical detection in a substantial fraction of cases.
In summary, CA 72-4 is a specialized marker primarily for follow-up of gastric cancer and selected mucinous ovarian tumors rather than a general screening test.