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FISH, p53, Deletion 17p13.1
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Test Code
P53FSH
Alias/See Also
17874
CPT Codes
88271 (x2), 88275
Preferred Specimen
3 mL bone marrow or 5 mL whole blood collected in sodium heparin (green-top) tube
Minimum Volume
1 mL bone marrow • 3 mL whole blood
Other Acceptable Specimens
Bone marrow or whole blood collected in: sodium heparin (royal blue-top) tube, or sodium heparin lead-free (tan-top) tube • Bone marrow submitted in culture transport media • 5x5mm fresh lymph node, or fresh biopsy in culture transport medium (transport medium available upon request)
Instructions
Clinical history and reason for referral is required with test order. Prior therapy and transplant history should be provided with test order. Please specify if this test is run for plasma cell neoplasms.
Specimen viability decreases during transit. Send specimen to testing lab for viability determination. Do not freeze. Do not reject.
Specimen viability decreases during transit. Send specimen to testing lab for viability determination. Do not freeze. Do not reject.
Transport Temperature
Fresh lymph node: Refrigerated (cold packs)
All other specimens: Room temperature
All other specimens: Room temperature
Specimen Stability
Room temperature: See instructions
Refrigerated: See instructions
Frozen: See instructions
Refrigerated: See instructions
Frozen: See instructions
Methodology
Fluorescence in situ Hybridization (FISH)
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Daily; Report available: 5 days
Clinical Significance
This fluorescence in situ hybridization (FISH) assay detects deletion of the TP53 gene region in chromosome 17p13.1. The results of this test may aid in the prognostic assessment and treatment selection for chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL).
The most common genetic abnormalities of CLL/SLL are del(13q), del(11q), trisomy 12, and del (17p). At least one of these 4 genetic abnormalities can be detected with FISH in >80% of patients with CLL/SLL [1]. Evaluation of these frequent genetic abnormalities is recommended for the investigation of prognosis [2] and may inform treatment decisions [3].
Del(17p) can be detected with FISH in 7% of patients with CLL/SLL and confers unfavorable prognosis [1]. Del(17p) results in the loss of the TP53 gene and can occur concurrently with mutations in the remaining TP53 allele. The abnormalities of the TP53 gene are the strongest genetic predictor of prognosis and treatment outcome and may be present before therapy or emerge after therapy [1,2]. Therefore, testing for both the deletion and mutation of the TP53 gene is recommended before initiation of the therapy to inform therapy selection and at progression in patients without previously identified TP53 abnormalities [1,2].
A combination of genetic techniques is often involved in identifying genetic abnormalities. FISH testing is complementary to conventional cytogenetic analysis (karyotyping) and can be used to detect common cytogenetic abnormalities. However, because FISH is limited to probing specific chromosomal regions, it does not replace conventional cytogenetic analysis or chromosomal microarray for screening unknown abnormalities.
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Dohner H, et al. N Engl J Med. 2000;343(26):1910-1916.
2. Naresh KN, et al. B-cell lymphoid proliferations and lymphomas. In: WHO Classification of Tumours Editorial Board. The World Health Organization Classification of Haematolymphoid Tumours. 5 Beta V2 ed. IARC Press; 2022:chap 4. Accessed June 16, 2023. https://tumourclassification.iarc.who.int
3. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Chronic lymphocytic leukemia/small lymphocytic lymphoma. Version 3.2023. Updated June 12, 2023. https://www.nccn.org
The most common genetic abnormalities of CLL/SLL are del(13q), del(11q), trisomy 12, and del (17p). At least one of these 4 genetic abnormalities can be detected with FISH in >80% of patients with CLL/SLL [1]. Evaluation of these frequent genetic abnormalities is recommended for the investigation of prognosis [2] and may inform treatment decisions [3].
Del(17p) can be detected with FISH in 7% of patients with CLL/SLL and confers unfavorable prognosis [1]. Del(17p) results in the loss of the TP53 gene and can occur concurrently with mutations in the remaining TP53 allele. The abnormalities of the TP53 gene are the strongest genetic predictor of prognosis and treatment outcome and may be present before therapy or emerge after therapy [1,2]. Therefore, testing for both the deletion and mutation of the TP53 gene is recommended before initiation of the therapy to inform therapy selection and at progression in patients without previously identified TP53 abnormalities [1,2].
A combination of genetic techniques is often involved in identifying genetic abnormalities. FISH testing is complementary to conventional cytogenetic analysis (karyotyping) and can be used to detect common cytogenetic abnormalities. However, because FISH is limited to probing specific chromosomal regions, it does not replace conventional cytogenetic analysis or chromosomal microarray for screening unknown abnormalities.
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Dohner H, et al. N Engl J Med. 2000;343(26):1910-1916.
2. Naresh KN, et al. B-cell lymphoid proliferations and lymphomas. In: WHO Classification of Tumours Editorial Board. The World Health Organization Classification of Haematolymphoid Tumours. 5 Beta V2 ed. IARC Press; 2022:chap 4. Accessed June 16, 2023. https://tumourclassification.iarc.who.int
3. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Chronic lymphocytic leukemia/small lymphocytic lymphoma. Version 3.2023. Updated June 12, 2023. https://www.nccn.org
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Dr
Chantilly, VA 20153
