Marker of myeloid cancers:
**Core Concept**
The question is testing the understanding of a specific biomarker associated with myeloid cancers, which are a group of blood cancers that originate from the myeloid lineage of blood cells. This biomarker is a key diagnostic and prognostic tool in the management of these cancers.
**Why the Correct Answer is Right**
The correct answer is **FLT3** (Fms-like tyrosine kinase 3). FLT3 is a receptor tyrosine kinase that is involved in the regulation of cell proliferation and differentiation. In myeloid cancers, such as acute myeloid leukemia (AML), FLT3 mutations are common and are associated with a poor prognosis. The FLT3-ITD mutation, in particular, is a marker of myeloid cancers and is used to guide treatment decisions.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not correspond to a known biomarker of myeloid cancers.
**Option B:** This option is incorrect because it is a biomarker associated with lymphoid cancers, not myeloid cancers.
**Option C:** This option is incorrect because it is a biomarker associated with a different type of cancer.
**Clinical Pearl / High-Yield Fact**
FLT3 mutations are a key prognostic factor in AML, and their presence can guide treatment decisions, including the use of FLT3 inhibitors.
**Correct Answer:** C. FLT3.