Were you looking instead for the Alkaline Phosphatase test, also known as ALK PHOS or ALP, used in the evaluation of liver or bone disease? If so, go to the ALP article.
At a Glance
Why Get Tested?
To detect an ALK gene rearrangement in tumor tissue in order to guide non-small cell lung cancer therapy
When to Get Tested?
When you have been diagnosed with non-small cell lung cancer and your doctor is considering a therapeutic management plan that may include an ALK kinase inhibitor such as crizotinib
A sample of tumor tissue
Test Preparation Needed?
The Test Sample
What is being tested?
ALK is a short name for the anaplastic lymphoma receptor tyrosine kinase gene. This test detects specific rearrangements in the ALK gene in the DNA of cancer cells and tissue. The presence of these changes makes it more likely that a person with non-small cell lung cancer will respond to a targeted drug therapy.
The ALK gene codes for a protein called anaplastic lymphoma kinase. It is part of a family of proteins called receptor tyrosine kinases that transmit signals into cells and are thought to help regulate the proliferation of nerve cells.
About 5% of people who have non-small cell lung cancer, the most common type of lung cancer, have an alteration on chromosome 2 that leads to the fusion of the ALK gene with another gene called EML4 and results in the production of an EML4-ALK fusion protein. It is a rare mutation most commonly seen in people who have never smoked or are light smokers, especially women of Asian descent.
This gene mutation and abnormal protein production promotes the uncontrolled growth of cancer cells, but it also makes it more likely that the affected person will respond to a drug that targets the abnormal protein (an ALK kinase inhibitor, such as crizotinib) and less likely that the person will respond to tyrosine kinase inhibitors that target the EGFR (epidermal growth factor receptor).
There are several different methods of testing for ALK mutations, but all of them involve evaluating either the ALK gene rearrangement or the altered ALK protein in tumor tissue.
How is the sample collected for testing?
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Markman, M. (Updated 2013 July 15). Genetics of Non-Small Cell Lung Cancer. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1689988-overview through http://emedicine.medscape.com. Accessed July 2013.
Lindeman, N. et. al. (2013 June). Molecular Testing Guideline for Selection of Lung Cancer Patients for EGFR and ALK Tyrosine Kinase Inhibitors, Guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Arch Pathol Lab Med v 137, [On-line information]. Available online at http://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2012-0720-OA through http://www.archivesofpathology.org. Accessed July 2013.
Wallander, M. et. al. (Updated 2013 July) Lung Cancer. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/LungCancer.html?client_ID=LTD through http://www.arupconsult.com. Accessed July 2013.
(Revised 2012 March 21). Crizotinib. American Cancer Society [On-line information]. Available online at http://www.cancer.org/treatment/treatmentsandsideeffects/guidetocancerdrugs/crizotinib through http://www.cancer.org. Accessed July 2013.
Chustecka, Z. (2012 September 30). Crizotinib Now Standard of Care for ALK+ NSCLC. Medscape Medical News from the 2012 European Society for Medical Oncology (ESMO) Congress [On-line information]. Available online at http://www.medscape.com/viewarticle/771853 through http://www.medscape.com. Accessed July 2013.
Markman, M. (2012 April 4). How Does Genetics Affect Outcomes in Nonsmokers With NSCLC? Medscape Today News from Cancer v 118: 729-739. [On-line information]. Available online at http://www.medscape.com/viewarticle/761054 through http://www.medscape.com. Accessed July 2013.
(2013 June 17). Crizotinib Improves Progression-Free Survival in Some Patients with Advanced Lung Cancer. National Cancer Institute [On-line information]. Available online at http://www.cancer.gov/clinicaltrials/results/summary/2013/crizotinib-NSCLC0613 through http://www.cancer.gov. Accessed July 2013.
(Reviewed 2011 March). ALK. Genetics Home Reference [On-line information]. Available online at http://ghr.nlm.nih.gov/gene/ALK through http://ghr.nlm.nih.gov. Accessed July 2013.
Mulcahy, N. (2012 March 22). NSCLC Guidelines From NCCN Full of Change. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/760722 through http://www.medscape.com. Accessed July 2013.
(Updated 2010 June) Getting the Facts, Anaplastic Large Cell Lymphoma. Lymphoma Research Foundation [On-line information]. Available online at http://www.lymphoma.org/atf/cf/%7B0363cdd6-51b5-427b-be48-e6af871acec9%7D/ANAPLASTIC10.PDF through http://www.lymphoma.org. Accessed July 2013.
(2012 May 16). Drug used in NIH-supported trial shows benefit in children with previously treated cancers. National Cancer Institute [On-line information]. Available online at http://www.cancer.gov/newscenter/newsfromnci/2012/crizotinib through http://www.cancer.gov. Accessed July 2013.
Nelson, R. (2011 August 26). FDA Approves New Drug for Advanced NSCLC. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/748675 through http://www.medscape.com. Accessed July 2013.
Nelson, R. (2012 October 25). Crizotinib Receives Conditional Marketing Approval in Europe. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/773280 through http://www.medscape.com. Accessed July 2013.
(Revised 2012 October 18). Tumor Markers. American Cancer Society [On-line information]. Available online through http://www.cancer.org. Accessed July 2013.
Yi E., et al. Correlation of IHC and FISH for ALK Gene Rearrangement in Non-small Cell Lung Carcinoma: IHC Score Algorithm for FISH. Journal of Thoracic Oncology March 2011 - Volume 6 - Issue 3 - Pp 459-465. Available online at http://journals.lww.com/jto/Fulltext/2011/03000/Correlation_of_IHC_and_FISH_for_ALK_Gene.8.aspx# through http://journals.lww.com. Accessed November 2013.
Gregory J. Tsongalis, PhD, HCLD, CC, Professor of Pathology, Director, Molecular Pathology, Dartmouth Hitchcock Medical Center and Geisel School of Medicine at Dartmouth, Lebanon, NH.