Mobile Site ›
Communique Print the PDF of this entire issue

Test Update



Subscribe

Receive notification when new Communiqué articles are published:

January 2012

Test Update 1

FLCA/60619 Lung Cancer, ALK (2p23) Rearrangement, FISH, Tissue: FDA-Approved FISH Probe for Detection of ALK Gene Rearrangements in Patients with Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer death in the United States. Non-small cell lung carcinoma (NSCLC) accounts for 75% to 80% of all lung cancers, with an overall 5-year survival rate of 10% to 15%. Standard chemotherapy regimens have had marginal success in improving clinical outcomes. As novel molecular changes in these tumors are identified, targeted treatments may be used.

Rearrangement of the anaplastic lymphoma kinase gene (ALK) on chromosome 2p23 has been identified in 3% to 5% of NSCLC. The Mayo Clinic Cytogenetics Laboratory now offers a test to detect ALK gene rearrangement by using an FDA-approved ALK break-apart fluorescent in situ hybridization (FISH) probe set. The test is used as a companion diagnostic test to identify those patients eligible for treatment with Xalkori (crizotinib), a chemotherapy drug that was recently approved by the FDA to treat patients with late-stage (locally advanced or metastatic) NSCLC who express the ALK gene rearrangement.

Recent studies have demonstrated that lung cancers harboring ALK rearrangements are resistant to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, but may be highly sensitive to ALK inhibitors, like Xalkori. This drug works by blocking certain kinases, including those produced by the abnormal ALK gene, and clinical studies have shown that use of Xalkori in patients with this type of tumor can halt tumor progression or result in tumor regression. Therefore, this FDA-approved FISH assay can be used to identify patients who will likely benefit from Xalkori therapy.

Clinical References

1. FDA approves Xalkori with companion diagnostic for a type of late-stage lung cancer. FDA News Release Aug 26, 2011
2. Kwak EL, Bang YJ, Camidge DR, et al: Anaplastic lymphoma kinase inhibition in non-small-cell lung cancer. N Engl J Med. 2010 Oct 28;363(18):1693–1703
3. Shaw AT, Yeap BY, Solomon BJ, et al: Effect of crizotinib on overall survival in patients with advanced non-small-cell lung cancer harbouring ALK gene rearrangement: a retrospective analysis. Lancet Oncol 2011;12:1004–1012

Test Update 2

Guidelines for Metal-Free Specimen Handling and Processing

General Information for Venipuncture Collection

1. Do not collect specimens from patients who have received gadolinium-, iodine-, or barium-containing contrast material within the past 96 hours, as these substances are known to interfere with most metals tests.
2. Blood specimens for serum testing should be drawn in the plain, royal blue-top Monoject Trace Element Blood Collection Tube, product #8881-307006 (Supply T184).
3. Always use an alcohol swab to cleanse the venipuncture site. Avoid iodine-containing disinfectants.
4. Use only stainless steel phlebotomy needles.
5. Order of draw: When multiple blood specimens are scheduled for collection from a patient, the trace metal specimens should be collected first. Once the phlebotomy needle has punctured another rubber stopper, it is contaminated and should not be used for trace metal specimen collection.

Specimen Processing for Serum

1. Keep patient specimen area clean and free of dust.
2. Allow the specimen to clot for 30 minutes; then centrifuge the specimen to separate serum from the cellular fraction. Do not leave serum on cells more than 60 minutes.
3. Remove the stopper and carefully pour the serum into a 7-mL Mayo Medical Laboratories metal-free, screw-capped, polypropylene vial (Supply T173); avoid transfer of the cellular components of blood.
4. Do not insert a pipet into the serum to accomplish transfer.
5. Do not ream the specimen with a wooden stick to assist with serum transfer.
6. Do not touch specimen with utensils unless they have been acid-washed.
7. Place the cap tightly on the polypropylene vial, attach a specimen label, and send specimen to the laboratory at appropriate temperature.
8. All specimens to be stored more than 48 hours should be frozen.

General Information for Urine Collection

1. A clean, plastic container with no metal cap or glued insert must be used.
2. Send specimen in a plastic, 13-mL urine tube or a clean, plastic aliquot container with no metal cap or glued insert.
3. Do not collect urine specimens in the environment in which exposure is likely to occur.
4. It is important that dust from clothing not contribute to the specimen contents.
5. Do not collect urine in metal-based containers such as metal urinals or pans.
6. Do not collect or transport urine in colored containers because of metals found in dyes.
7. Do not submit urine collected via latex catheter. Latex contains cadmium and chromium that will contaminate the sample.

 


Key