ALK 2p23 gene rearrangement Featured
Test Code
F ALK
Test Synonyms
2p23 gene rearrangement, EML4-ALK
Associations
NSCLC with ALK gene rearrangements can now be treated with Xalkori (crizotinib), FDA approved for late stage locally advanced or metastatic NSCLC.
Methodology
Fluorescence in situ Hybridization (FISH)
CPT Codes
Please contact a client service specialist at 800.932.2943
Turnaround Time
3 days
Specimen Requirements
- 2.0 mL (min. 1.0 mL) peripheral blood in sodium heparin preferred, EDTA accepted
- 1.0 mL (min. 0.5 mL) bone marrow in sodium heparin preferred, EDTA accepted
- 5 mm^3 fresh tissue in MPLN RPMI media
- 3.0 mL (min. 2.0 mL) FNA in MPLN RPMI media
- 10% neutral buffered formalin fixed paraffin embedded tissue
Specimen Stability
- Peripheral blood and bone marrow stable at 18-25°C for 72 hours
- Fresh tissue or FNA stable at 2-8°C for 72 hours
Storage & Handling
- Whole blood and bone marrow, ship ambient
- Fresh tissue, FNA or paraffin embedded tissue, ship in a Styrofoam container with a cool/refrigerated pack (Do not allow cool pack to directly contact sample.)
Causes for Rejection
Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells; Improper fixative
Reference Range
FISH results indicate whether rearrangement is present or absent.
In a normal cell, two yellow (orange/green fused) signals will be seen. In a cell with a translocation involving ALK, one orange and one green signal will be seen along with one yellow signal.
In a normal cell, two yellow (orange/green fused) signals will be seen. In a cell with a translocation involving ALK, one orange and one green signal will be seen along with one yellow signal.
Related Content
The t(2;5)(p23;q35) translocation results in the expression of a chimeric NPM-ALK protein and is associated with anaplastic large-cell lymphoma (ALCL). It is also associated with inflammatory myofibroblastic tumors (IMTs), rare soft tissue tumors occurring primarily in children and young adults. ALK gene rearrangements with fusion of the ALK gene at 2p23 to a number of different partner genes, have been identified. FISH can detect this rearrangement in either interphase or metaphase cells.
Description
The LSI dual break-apart rearragement probe contains two differently labelled probes on either sides of the breakpoint of the ALK gene. ALK has multiple fusion partners including NPM in anaplastic large cell lymphoma and EML4 in non small cell lung cancer.
EML4/ALK fusions are the result of paracentric inversions involving the short arm of chromosome 2. The breakpoints of the inversions are within the EML4 locus (2p21) and the ALK locus (2p23).
EML4/ALK fusions are the result of paracentric inversions involving the short arm of chromosome 2. The breakpoints of the inversions are within the EML4 locus (2p21) and the ALK locus (2p23).
References
- Soda et al. (2007). Identification of the transforming EML4-ALK fusion gene in non-small-cell lung cancer. Nature 448:561-566
- Rodig et al.(2009) Unique clinicopathologic features characterize ALK-Rearranged Lung Adenocarcinoma in Western Population. Clin Cancer Res 15:5216-5223
- Shaw et al. (2009) Clinical features and outcome of patients with non-small-cell lung cancer who harbor EML4-ALK, JCO 26:4247-4253
- Patel Ankita et al. (2007). Cancer Genetics and Cytogenetics. 176:107-114.
- Onciu M et al. (2003). ALK-positive anaplastic large cell lymphoma with leukemic peripheral blood involvement is a clinicopathologic entity with an unfavorable prognosis. Am J Clin Pathol. 120(4):617.
- Liang X et al. (2004). Assessment of t(2;5)(p23;q35) translocations and variants in pediatric ALK+ anaplastic large cell lymphoma. Am J Clin Pathol. 121(4):496.