Tumor marker CA 15-3 is associated with ?
**Core Concept**
CA 15-3 is a tumor marker that is primarily associated with breast cancer. It is a mucin-type glycoprotein that is expressed on the surface of certain cancer cells, particularly in breast cancer.
**Why the Correct Answer is Right**
CA 15-3 is used as a biomarker for monitoring breast cancer recurrence and metastasis. Elevated levels of CA 15-3 are often seen in patients with advanced breast cancer, such as those with metastatic disease. The CA 15-3 antigen is expressed on the surface of breast cancer cells and is shed into the bloodstream, where it can be detected using immunoassays.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is missing.
* **Option B:** This option is also missing.
* **Option C:** This option is incorrect because while CA 15-3 is associated with breast cancer, it is not a marker for ovarian cancer.
**Clinical Pearl / High-Yield Fact**
CA 15-3 levels can be elevated in other conditions, such as pregnancy and benign breast diseases, which can lead to false-positive results. Therefore, a diagnosis of breast cancer should be based on a combination of clinical evaluation, imaging studies, and other tumor markers.
**Correct Answer: C. Breast cancer.**