**Core Concept**
Gastrointestinal Stromal Tumors (GISTs) are a type of mesenchymal tumor originating from the interstitial cells of Cajal or their precursors, which are found in the gastrointestinal tract. GISTs are characterized by mutations in the KIT or PDGFRA genes, leading to uncontrolled cell proliferation.

**Why the Correct Answer is Right**
The correct answer will relate to a characteristic of GISTs that is not true. GISTs are typically slow-growing and often present with abdominal pain, bleeding, or a palpable mass. They are most commonly found in the stomach (60-70%) or small intestine (20-30%). The KIT gene mutation is present in 70-80% of GISTs, leading to constitutive activation of the KIT tyrosine kinase.

**Why Each Wrong Option is Incorrect**
* **Option A:** GISTs are typically aggressive and have a high propensity for metastasis. **Incorrect because** GISTs are generally slow-growing and have a low metastatic potential compared to other types of tumors.
* **Option B:** GISTs are most commonly found in the colon. **Incorrect because** while GISTs can occur in the colon, they are more commonly found in the stomach or small intestine.
* **Option C:** The KIT gene mutation is present in 100% of GISTs. **Incorrect because** while the KIT gene mutation is present in 70-80% of GISTs, it is not present in all cases.

**Clinical Pearl / High-Yield Fact**
GISTs are often mistaken for other types of tumors, such as leiomyomas or adenocarcinomas, but can be distinguished by their typical location and histological features.

**Correct Answer: D. The KIT gene mutation is present in 100% of GISTs. The KIT gene mutation is present in 70-80% of GISTs.**