NPM–ALK — oncology-focused definition
NPM–ALK is a fusion gene created by the t(2;5)(p23;q35) translocation, which combines:
- NPM (nucleophosmin) gene on chromosome 5
- ALK (anaplastic lymphoma kinase) gene on chromosome 2
Oncology relevance:
- Causes constitutive ALK tyrosine kinase activity, leading to uncontrolled proliferation and survival of lymphoid cells.
- Found in ALK-positive anaplastic large cell lymphoma (ALCL), most often in children and young adults.
Clinical significance (for oncology pharmacists):
- Diagnostic marker: Confirms ALK+ ALCL; detected by FISH, immunohistochemistry, or RT-PCR.
- Therapeutic relevance:
- Targetable with ALK inhibitors (e.g., crizotinib, ceritinib) in relapsed or refractory disease.
- Guides treatment planning and prognosis.
- Prognosis: ALK+ ALCL generally has a better prognosis than ALK-negative ALCL.
Key takeaway:
NPM–ALK is a driver fusion in ALK+ ALCL, making it a diagnostic and targetable biomarker, crucial for precision therapy.
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