Synovial Sarcoma (SS), 18q11.2 (SS18 or SYT) 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 synovial sarcoma when used in conjunction with an anatomic pathology consultation
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
SS18 (SYT), 18q11.2, 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
Synovial sarcoma (SS) is a malignant soft tissue tumor that predominantly occurs in the lower limbs of children and young adults. This tumor accounts for approximately 5% to 10% of soft tissue tumors, has a poor prognosis, and may occur in other areas of the body such as the head and neck, heart, abdominal wall, mediastinum, and lung, in addition to the extremities. Histologically, SS is grouped either into the monophasic subtype consisting of mostly spindle cells or the biphasic subtype consisting of epithelial and spindle cells. Depending on the site of origin, the differential diagnosis of SS can include mesothelioma, fibrosarcoma, solitary fibrous tumor, leiomyosarcoma, malignant peripheral nerve sheath tumors, epithelioid sarcoma, and clear cell sarcoma. In addition, when the SS is poorly differentiated, the differential diagnosis broadens to include the small round-blue cell tumors (Ewing sarcoma, alveolar rhabdomyosarcoma, and neuroblastoma). Accurate diagnosis of SS is important for appropriate clinical management of patients. Although immunohistochemical markers can be helpful in the correct diagnosis of these various tumor types, recent molecular studies have shown the superior specificity of molecular makers in differentiating SS from other tumors.
A recurrent, tumor-specific translocation t(X;18)(p11.2q11.2) is observed in approximately 90% of synovial sarcomas. A single gene, SS18 (SYT), has been implicated on 18q11.2, while 1 of 3 related genes, SSX1, SSX2, or infrequently SSX4, is usually involved on Xp11.2. The prevalence of SS18-SSX1 is about twice that of SS18-SSX2 in most studies. Detection of these transcripts is usually performed by reverse transcriptase-PCR (RT-PCR) (83361 Synovial Sarcoma by Reverse Transcriptase PCR [RT-PCR], Paraffin), which allows specific identification of SS18-SSX1 or SS18-SSX2. Identification of the SS18-SSX1 fusion is associated with an unfavorable outcome with significantly shorter overall survival when compared to the SS18-SSX2 fusion. Unfortunately, RT-PCR results may be equivocal or falsely negative due to many reasons such as when the available RNA is of poor quality or if a rare translocation partner is present. In these cases, FISH testing can be used to identify SS18 gene rearrangements in these tumors, which supports the diagnosis of SS.
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 SYT FISH probe. A positive result suggests rearrangement of the SYT gene region at 18q11.2 and supports the diagnosis of SS. A negative result suggests no rearrangement of the SYT gene region at 18q11.2. However, this result does not exclude the diagnosis of SS.
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 nonformalin 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 36 formalin-fixed, paraffin-embedded tissue samples including 14 synovial sarcoma (SS) tumors and 22 noncancerous controls or non-SS tumors. The normal controls were used to generate a normal cutoff for this assay. Each SS specimen had been previously characterized to carry the t(X;18) via reverse transcriptase-PCR analysis. Eleven tumors had the SSX1 translocation partner and 3 tumors had the SSX2 translocation partner. Rearrangement of SS18 was identified in all 14 SS specimens with the expected break-apart signal pattern observed in 10 patients and 4 patients demonstrated atypical break-apart signal patterns.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Fisher C, de Brujin DRH, Guerts van Kessel A: Chapter IX: Synovial sarcoma. 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 200-204
2. Sandberg AA, Bridge JA: Updates on the cytogenetics and tissue tumors. Synovial sarcoma. Cancer Genet Cytogenet 2002 Feb;133(1):1-23
3. Kokovic I, Bracko M, Golouh R, et al: Are there geographical chimeric transcripts in synovial sarcoma? Cancer Detect Prev 2004;28(4):294-301
Method Description Describes how the test is performed and provides a method-specific reference
The test uses a commercially available SS18 (SYT) dual-color, break-apart probe strategy. Formalin-fixed, paraffin-embedded tissues are cut at 5 microns and mounted on positively-charged glass slides. The selection of tissue and the target areas on the hematoxylin and eosin (H and E)-stained slide is performed by a pathologist. Using the H and E slide 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|
|CG261||Reason For Referral||42349-1|