Not a specific tumor marker is –
## **Core Concept**
The question tests the knowledge of tumor markers, which are substances produced by cancer cells or in response to cancer. Tumor markers can be used for diagnosing, monitoring, and predicting the prognosis of various cancers.
## **Why the Correct Answer is Right**
Alpha-fetoprotein (AFP) is a tumor marker specifically associated with hepatocellular carcinoma and certain germ cell tumors. Human chorionic gonadotropin (hCG) is another specific marker, often elevated in choriocarcinoma and some other germ cell tumors. Prostate-specific antigen (PSA) is used primarily as a marker for prostate cancer. Carcinoembryonic antigen (CEA) is more of a general marker that can be elevated in several types of cancers, including colorectal, breast, lung, and others, but it is not specific to a single type of cancer.
## **Why Each Wrong Option is Incorrect**
- **Option A:** AFP is specifically associated with hepatocellular carcinoma.
- **Option B:** hCG is specifically elevated in choriocarcinoma and some germ cell tumors.
- **Option D:** PSA is a specific marker for prostate cancer.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while CEA (Carcinoembryonic antigen) can be elevated in various cancers, it is not specific to any one cancer type, making it less useful as a diagnostic tool but still valuable for monitoring disease recurrence.
## **Correct Answer:** . Carcinoembryonic antigen (CEA).