Most common cytogenetic abnormality in Multiple myeloma is
**Core Concept**
Multiple myeloma is a type of plasma cell dyscrasia characterized by clonal proliferation of malignant plasma cells in the bone marrow. Cytogenetic abnormalities play a crucial role in the pathogenesis and progression of this disease.
**Why the Correct Answer is Right**
The most common cytogenetic abnormality in multiple myeloma is the deletion of chromosome 13 (13q14 deletion). This deletion involves the loss of the RB1 gene, which encodes a tumor suppressor protein that regulates cell cycle progression. The loss of RB1 function contributes to the uncontrolled proliferation of malignant plasma cells. Other common cytogenetic abnormalities in multiple myeloma include translocations involving the immunoglobulin heavy chain locus (IgH) on chromosome 14, such as t(4;14) and t(14;16), and deletions involving chromosome 17p (p53 gene).
**Why Each Wrong Option is Incorrect**
**Option A:** Deletion of chromosome 7 is not a common cytogenetic abnormality in multiple myeloma.
**Option B:** Translocation t(11;14) involving the cyclin D1 gene is more commonly associated with mantle cell lymphoma.
**Option C:** Deletion of chromosome 5 is not a well-documented cytogenetic abnormality in multiple myeloma.
**Clinical Pearl / High-Yield Fact**
The presence of cytogenetic abnormalities in multiple myeloma can have significant implications for patient prognosis and treatment. For example, patients with deletion 13q14 may have a poorer prognosis compared to those without this abnormality.
**Correct Answer:** C. Deletion of chromosome 13 (13q14 deletion).