Ewing Sarcoma (EWS) 22q12 Rearrangement, FISH, Tissue
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Supporting the diagnosis of Ewing sarcoma (EWS)/primitive neuroectodermal tumor (PNET), myxoid chondrosarcoma, desmoplastic small, round cell tumor, clear cell sarcoma, and myxoid liposarcoma when used in conjunction with an anatomic pathology consultation
An aid in the diagnosis of EWS when reverse transcriptase-PCR results are equivocal or do not support the clinical picture
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
This test does not include a pathology consult. If a pathology consultation is requested, 70012 Pathology Consultation should be ordered and the appropriate FISH test will be ordered and performed at an additional charge.
Fluorescence In Situ Hybridization (FISH)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
EWSR1, 22q12, FISH
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Please provide a pathology report with each specimen. The laboratory will not reject a specimen that arrives without this information but will hold the specimen until a pathology report is received.
Submit only 1 of the following specimens:
Preferred: Formalin-fixed, paraffin-embedded tumor tissue block and 1 hematoxylin and eosin (H and E)-stained slide
Acceptable: Four consecutive, unstained, 5 micron-thick sections placed on positively-charged slides and 1 H and E-stained slide
Forms: If not ordering electronically, complete and submit a Hematopathology/Molecular Oncology Request Form (Supply T241) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
2 unstained slides and 1 hematoxylin-and-eosin (H and E) slide
Note: No specimen should be rejected. If specimen not received at appropriate temperature or in wrong anticoagulant, include note to laboratory. If questions, contact laboratory.
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Ewing sarcoma (EWS)/primitive neuroectodermal tumors (PNET) are members of the small, round cell group of tumors that are thought to originate in cells of primitive neuroectodermal origin with variable degrees of differentiation. The small, round cell group of tumors also includes rhabdomyosarcomas, desmoplastic small, round cell tumors, and poorly differentiated synovial sarcomas. Although immunohistochemical markers can be helpful in the correct diagnosis of these tumors, recent molecular studies have shown the specificity of molecular markers in differentiating specific subtypes of small, round blue-cell tumors. Accurate diagnosis of each tumor type is important for appropriate clinical management of patients.
Ewing tumors are characterized cytogenetically by rearrangements of the EWSR1 gene at 22q12 with FLI1 at 11q24 (t[11;22]) or ERG at 21q22 (t[21;22]) in 85% and 5% to 10% of Ewing tumors, respectively. Less than 1% of cases may have other fusion partners such as ETV1 at 7p22, E1AF at 17q12, or FEV at 2q33. Detection of these transcripts by reverse transcriptase-PCR (RT-PCR) (83363 Ewing Sarcoma/Primitive Neuroectodermal Tumors (ES/PNET) by Reverse Transcriptase PCR (RT-PCR), Paraffin) that allows specific identification of the t(11;22) and the t(21;22), has greatly facilitated the diagnosis of Ewing tumors. However, if the quality of the available RNA is poor, the results are equivocal, or if a rare translocation partner is present, FISH testing has proven to be useful in identifying the 22q12 EWS gene rearrangement in these tumors.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretive report will be provided.
A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal cutoff for the EWSR1 FISH probe set.
A positive result is consistent with a diagnosis of Ewing sarcoma (EWS)/primitive neuroectodermal tumors (PNET).
A negative result suggests that a EWSR1 rearrangement is not present but does not exclude the diagnosis of EWS/PNET.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test is not approved by the FDA and is best used as an adjunct to existing clinical and pathologic information.
Fixatives other than formalin (eg, Prefer, Bouin's) may not be successful for FISH assays. Although FISH testing will not be rejected due to non-formalin fixation results may be compromised.
Paraffin-embedded tissues that have been decalcified are generally unsuccessful for FISH analysis. The pathologist reviewing the hematoxylin and eosin-stained slide may find it necessary to cancel testing.
FISH analysis was performed on 38 formalin-fixed, paraffin-embedded tissue samples, 16 tumors, and 22 noncancerous control specimens. The normal controls were used to generate a normal cutoff for this assay. Rearrangement of EWSR1 was identified in 14 tumor specimens and 2 yielded no results due to poor hybridization.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Ushigome S, Machinami R, Sorensen PH: Chapter XIV: Ewing sarcoma/Primitive neuroectodermal tumour (PNET). In World Health Organization Classification of Tumors. Pathology and Genetics of Tumours of Soft Tissue and Bone. Edited by CDM Fletcher, KK Unni, F Mertens. Lyon, IARC Press, 2002, pp 298-300
2. Burchill SA: Ewing's sarcoma: diagnostic, prognostic, and therapeutic implications of molecular abnormalities. J Clin Pathol 2003 February;56(2):96-102
3. Riley RD, Burchill SA, Abrams KR, et al: A systematic review of molecular and biological markers in tumors of the Ewing's sarcoma family. Eur J Cancer 2003 January;39:19-30
Method Description Describes how the test is performed and provides a method-specific reference
This test uses a commercially available EWSR1 dual-color break-apart probe strategy. Formalin-fixed, paraffin-embedded tissues are cut at 5 microns and mounted on positive charged glass slides. The selection of tissue and the identification of target areas on an hematoxylin and eosin (H and E)-stained slide is performed by a pathologist. Using the H and E as a reference, target areas are etched with a diamond tipped etcher on the back of the unstained slide to be assayed. The probe set is hybridized to the appropriate target areas and 2 technologists each analyze 100 interphase nuclei each (200 total) with the results expressed as a percent abnormal nuclei.(Unpublished Mayo method)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Samples processed Monday through Sunday. Results reported Monday through Friday 8am-5pm CST
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
88271 x 2-DNA probe, each
88275-Interphase in situ hybridization, 100-300 cells
88291-Interpretation and report
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|CG072||Reason For Referral||42349-1|