**Core Concept**
Encorafenib is a potent and selective inhibitor of mutated BRAF V600, a key driver of cancer cell proliferation in various malignancies. This molecular targeted therapy aims to exploit the aberrant signaling pathway in BRAF-mutated tumors.

**Why the Correct Answer is Right**
Encorafenib works by covalently binding to the ATP-binding site of BRAF V600, thereby inhibiting its enzymatic activity and downstream signaling. This leads to a decrease in the MAPK/ERK pathway activity, ultimately resulting in cell cycle arrest and apoptosis in BRAF V600-mutated cancer cells. Encorafenib has been approved for use in combination with binimetinib for the treatment of patients with unresectable or metastatic melanoma with a BRAF V600E or V600K mutation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as encorafenib is not primarily used for the treatment of colon cancer. While BRAF mutations do occur in colon cancer, encorafenib's efficacy and approval are specifically tied to BRAF-mutated melanoma.
**Option B:** This option is incorrect as encorafenib is not a tyrosine kinase inhibitor (TKI). Although it targets a protein kinase, its mechanism of action is distinct from traditional TKIs.
**Option C:** This option is incorrect as there is no FDA approval for encorafenib in the treatment of leukemia. While BRAF mutations can occur in various cancers, encorafenib's current indication is limited to BRAF-mutated melanoma.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that BRAF V600 mutations are not exclusive to melanoma and can occur in other cancers, such as colorectal, thyroid, and hairy cell leukemia. However, the efficacy and FDA approval of encorafenib are specifically tied to its use in BRAF-mutated melanoma.

**Correct Answer: A. Metastatic Melanoma**