t(9;22)(q34;q11) translocation is commonly associated with: September 2007
## **Core Concept**
The question tests knowledge of specific cytogenetic abnormalities associated with hematological malignancies. The translocation t(9;22)(q34;q11) is a well-known genetic abnormality in hematology. This specific translocation involves the fusion of parts of chromosome 9 and chromosome 22.
## **Why the Correct Answer is Right**
The correct answer, , is associated with the t(9;22)(q34;q11) translocation, also known as the Philadelphia chromosome. This translocation results in the fusion of the BCR (breakpoint cluster region) gene on chromosome 22 with the ABL1 gene on chromosome 9, creating the BCR-ABL1 fusion gene. This fusion gene produces a tyrosine kinase enzyme that is always active and leads to uncontrolled proliferation of leukemic cells. The Philadelphia chromosome is a hallmark of chronic myeloid leukemia (CML) and is also found in some cases of acute lymphoblastic leukemia (ALL).
## **Why Each Wrong Option is Incorrect**
- **Option A:** - This option is incorrect because while is a type of leukemia, the specific translocation t(9;22)(q34;q11) is not characteristically associated with it; instead, it is more commonly linked to and some cases of .
- **Option B:** - This option is incorrect because, although can have various cytogenetic abnormalities, t(9;22)(q34;q11) is not typically one of them.
- **Option C:** - This option is incorrect because involves different cytogenetic abnormalities, not t(9;22)(q34;q11).
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that the presence of the Philadelphia chromosome (t(9;22)(q34;q11)) in a patient with or is a critical diagnostic and prognostic marker. The development of tyrosine kinase inhibitors (TKIs), such as imatinib, has significantly improved the treatment outcomes for patients with this abnormality.
## **Correct Answer Line**
**Correct Answer: D. Chronic Myeloid Leukemia (CML).**