Specific marker for GIST is?
**Core Concept**
The question is testing knowledge of **Gastrointestinal Stromal Tumors (GISTs)**, which are a type of tumor that occurs in the digestive tract. GISTs are known for their expression of specific markers that help in their diagnosis. **CD117**, also known as **c-Kit**, is a key receptor tyrosine kinase involved in the pathogenesis of GISTs.
**Why the Correct Answer is Right**
The correct answer is related to the expression of **c-Kit (CD117)**, which is a specific marker for GISTs. This is because most GISTs have mutations in the **c-Kit** gene, leading to its overexpression. **c-Kit** is a receptor tyrosine kinase that, when mutated, can lead to uncontrolled cell proliferation, contributing to the development of GISTs.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not specifically associated with GISTs.
**Option B:** Incorrect as it is not a primary marker for GISTs.
**Option C:** Incorrect because, although it may be expressed in some GISTs, it is not as specific as **c-Kit** for diagnosing GISTs.
**Option D:** Incorrect as it does not relate to the specific marker for GISTs.
**Clinical Pearl / High-Yield Fact**
Remembering that **c-Kit (CD117)** is a specific marker for GISTs is crucial for diagnosis and treatment planning. This knowledge can help differentiate GISTs from other types of tumors in the digestive tract.
**Correct Answer:** D. CD117.