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Test ID: DDIT3 FFPE FISH
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DDIT3 Gene rearrangement by FISH
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DDIT3 (12q13) Gene rearrangement detection by FISH.
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Useful For
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DDIT3 Break apart (12q13) probe is used for the diagnosis and management of soft tissue tumors to rule out myxoid/round cell liposarcoma.
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Method name and description
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This test is performed on FFPE tissues using FISH technique.
This test is performed on identified target areas of Formalin fixed paraffin embedded (FFPE) tissue which are cut at 4 microns and mounted onto positively charged slides. The area of target is selected with a diamond pen etched onto the back of the unstained slide concordantly with hematoxylin and eosin (H and E) stained slides performed by the pathologist. The slides are then processed using a commercially available DDIT3 (12q13) dual color break apart probe set in conjugation with fluorescence insitu hybridization (FISH) technique, analyzed by 2 technologists for a total of 200 interphase nuclei count, which is reported by the percentage of nuclei cells analyzed.
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Clinical information
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Myxoid or round cell liposarcoma are subset of Liposarcomas which is identified by DDIT3 rearrangement formerly also known as CHOP gene. DDIT3 gene rearrangement involving chromosome translocation with DDIT3/FUS t(12;16)(q13;p11), DDIT3/EWSR1 t(12;22)(q13;q12),and other variant rearrangements resulting in clinical significance of positive results supporting the histopathologic evaluation for the diagnosis of liposarcoma.
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Aliases
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DDIT3, (12q13), DDIT3/FUS t(12;16)(q13;p11), DDIT3/EWSR1 t(12;22)(q13;q12), Myxoid, round cell liposarcoma.
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Specimen type / Specimen volume / Specimen container
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Specimen Type: Tissue Slides
Specimen Volume: 1 stained Hematoxylin and Eosin (H and E) slide along with 2 concordant unstained tissue blocks cut at 4-micron selection mounted onto positively charged slides.
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Collection instructions / Special Precautions / Timing of collection
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Collection Instruction: Provide correctly labelled and marked Formalin fixed paraffin embedded (FFPE) tissue slides, 1 H and E stained slide along with 2 concordant unstained tissue blocks cut at 4- micron, prepared with a fixation method and mounted on positively charged slides.
Patient’s clinical details with appropriate reason for testing are required.
Patient’s pathology report (Surgical pathology, preliminary report) is required for testing to be performed.
Time of Collection: Sunday to Wednesday: 7am to 3pm.
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Storage and transport instructions
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FFPE slides are to be stored in the Slide box at 22⁰c - 26⁰c. Follow your local regulation shipping guidelines.
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Specimen Rejection Criteria
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Broken slides.
Unlabeled slides with patient/case identification
Contaminated slides
Slides / Paraffin blocks mismatch
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Factors affecting test performance and result interpretation
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Test Interpretation and Performance:
A positive result is consistent with the diagnosis of Myxoid/round cell liposarcoma which is reported when there is a rearrangement of the DDIT3 locus gene above the normal cutoff for the probe-set.
A negative result suggests that there is no DDIT3 gene rearrangement but does not exclude the diagnosis of liposarcoma.
The results should be correlated with other genetic, pathological and Clinical interpretations.
Limitations:
Rearrangement detection is only limited to the DDIT3 (12q13) probe region, any chromosomal alteration outside this region cannot be detected. The successful performance of this test is subject to proper fixation method of the tissue block onto positively charged slides in correlation with tumor area on marked H and E slides by the pathologist.
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround Time: 14 Days.
Days and Times tests performed: Sunday to Wednesday 7am to 3pm.
Specimen retention time:
Unstained slides and (H and E) stained slides are retained until 6 months in accordance with CAP standards and Laboratory guidelines.
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