Test ID: FCHOP
Myxoid/Round Cell Liposarcoma 12q13 (DDIT3 or CHOP) Rearrangement, FISH, Tissue
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
As an aid in the diagnosis of myxoid/round cell liposarcoma by detecting a neoplastic clone associated with gene rearrangement involving the CHOP gene region at 12213.
Method Name A short description of the method used to perform the test
Fluorescence In Situ Hybridization (FISH)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
FUS
GADD153
liposarcoma
t(12;16)
t(12;22)
TLS
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.
Provide a pathology report with each tissue specimen. The laboratory will not reject a specimen that arrives without this information but will hold the specimen until a pathology report is received.
Specimen Type: Tissue block and slide
Collection Instructions: Submit formalin-fixed, paraffin-embedded tumor tissue block and include 1 hematoxylin-and-eosin stained slide.
Forms: If not ordering electronically, submit a Cytogenetics Hematologic Disorders Request Form (Supply T607) 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.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Tissue | Ambient (preferred) | |
| Refrigerated | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Myxoid/round cell liposarcoma is the second most common subtype of liposarcoma, accounting for more than one third of all liposarcomas and representing about 10% of all adult soft-tissue sarcomas. Myxoid/round cell liposarcoma is described as a malignant tumor composed of uniform round to oval shaped primitive nonlipogenic mesenchymal cells and a variable number of small signet-ring lipoblasts in a prominent myxoid stroma with a characteristic branching vascular pattern.
A unique chromosome translocation, t(12;16) (q13;p11), resulting in a fusion of the DDIT3 gene (also known as CHOP or GADD153) on chromosome 12 and the FUS gene (also referred to as TLS) on chromosome 16, is the key genetic aberration in myxoid/round cell liposarcoma. More than 90% of myxoid/round cell liposarcoma are cytogenetically characterized by this translocation. In rare cases, a variant t(12;22)(q13;q12) has been described in which DDIT3 (CHOP) fuses with EWS, a gene highly related to FUS.
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.
Interpretation Provides information to assist in interpretation of the test results
A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal cutoff for the CHOP probe. A positive result is consistent with a subset of myxoid/round cell liposarcoma. A negative result suggests no rearrangement of the CHOP gene region at 12q13. However, this result does not exclude the diagnosis of myxoid/round cell liposarcoma.
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 it is best used as an adjunct to existing clinical and pathologic information.
Supportive Data
A blinded study using the CHOP break-apart probe set was performed on 51 paraffin embedded tissue samples including 26 myxoid/round cell liposarcomas and 25 normal soft tissue control specimens (from various anatomic locations). A rearrangement of CHOP was identified in 18 of 26 myxoid/round cell liposarcoma specimens. No CHOP rearrangements were detected in any of the control specimens.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Turc-Carel C, Limon J, Dal Cin P, et al: Cytogenetic studies of adipose tissue tumors. II. Recurrent reciprocal translocation t(12;16)(q13;p11) in myxoid liposarcomas. Cancer Genet Cytogenet 1986;23(4):291-299
2. Aman P, Ron D, Mandahl N, et al: Rearrangement of the transcription factor gene CHOP in myxoid liposarcomas with t(12;16)(q13;p11). Genes Chromosomes Cancer 1992;5(4):278-285
3. Antonescu CR, Elahi A, Humphrey M, et al: Specificity of TLS-CHOP rearrangement for classic myxoid/round cell liposarcoma: absence in predominantly myxoid well-differentiated liposarcomas. J Mol Diagn 2000;2(3):132-138
4. Antonescu C, Ladanyi M: Myxoid liposarcoma. In Pathology and Genetics of Tumours of Soft Tissue and Bone. World Health Organization Classification of Tumours. Vol 5. Edited by CDM Fletcher, K Unni, F Mertens. Lyon, IARC Press, 2002, pp 40-43
5. Meis-Kindblom JM, Sjogren H, Kindblom LG, et al: Cytogenetic and molecular genetic analyses of liposarcoma and its soft tissue simulators: recognition of new variants and differential diagnosis. Virchows Arch 2001;439(2):141-51
Method Description Describes how the test is performed and provides a method-specific reference
The test uses a CHOP dual-color, break-apart probe (BAP) strategy (Abbott Molecular). Paraffin-embedded tissues are cut at 5 microns and mounted on positively charged glass slides. Four slides are prepared, with 1 slide stained with hematoxylin-and-eosin (H&E). The selection of tissue and the identification of target areas on the H&E stained slide is performed by a pathologist. Using the H&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 analyze 100 interphase nuclei each (200 total) with the results expressed as percent abnormal nuclei. (Unpublished Mayo data)
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, 8 a.m.-5 p.m. 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.
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
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 |
|---|---|---|
| 27388 | Specimen | 31208-2 |
| 27389 | Specimen ID | N/A |
| 27390 | Source | N/A |
| 27391 | Order Date | N/A |
| CG061 | Reason For Referral | 42349-1 |
| 27393 | Method | In Process |
| 27394 | Result | In Process |
| 27395 | Interpretation | 69965-2 |
| 27396 | Amendment | In Process |
| 27397 | Consultant | N/A |
| 27398 | Released Date | N/A |
External
link
PDF
document
Excel
document
Word
document