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FISH, p53, Deletion 17p13.1
Test Code17874
CPT Codes
88271 (x2), 88275
Includes
If results are not possible, the test order may be canceled and replaced by code %39650 - Cytogenetics Communication.
Preferred Specimen
3 mL bone marrow or 5 mL whole blood collected in a sodium heparin (green-top) tube
Minimum Volume
Whole blood: 3 mL
Bone marrow: 1 mL
Lymph node or Fresh Biopsy: 5 x 5 mm
Bone marrow: 1 mL
Lymph node or Fresh Biopsy: 5 x 5 mm
Other Acceptable Specimens
5 x 5 mm Lymph node or Fresh biopsy collected in culture transport medium • Bone marrow or whole blood collected in sodium heparin (royal blue-top) or sodium heparin lead-free (tan-top)
Instructions
Clincial history and reason for referral are 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.
Please specify if this test is run for plasma cell neoplasms.
Transport Temperature
Room temperature
Specimen Stability
Specimen viability decreases during transit. Send specimen to testing lab for viability determination. Do not freeze. Do not reject.
Methodology
Fluorescence in situ Hybridization (FISH)
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
