Myeloproliferative Neoplasms/ Myeloproliferative Disorders (MPN/MPD) Panel
CPT Code(s)
88271x4, 88275x4
Performed
Clinical & Molecular Cytogenetics Laboratory
Clinical Indication and Relevance
Fluorescence in situ hybridization (FISH) is a sensitive method to detect smaller genomic changes associated with various hematological malignancies and solid tumors. There are several advantages with FISH technology over routine chromosome analysis and such advantages include the ability of FISH technology to detect genomic abnormalities in non-viable and non-dividing tissues, rapid turnaround time, and increased resolution. However, FISH technology is complementary to routine chromosome analysis and cannot substitute routine chromosome analysis for diagnosis of cancer.
Clinical Background
Myeloproliferative neoplasms associated with activated tyrosine kinase and presenting with eosinophilia are a distinct group of myeloproliferative and lymphoid neoplasms. These neoplasms, especially those with rearrangements involving the platelet derived growth factor receptor alpha (PDGFRA), platelet derived growth factor receptor beta (PDGFRB), fibroblast growth factor receptor 1 (FGFR1) and BCR/ABL1 fusion, respond well to treatment with tyrosine kinase inhibitors like imatinib and hence are called imatinib responsive neoplasms.
The most common chromosomal rearrangements seen in this group include t(4;12) resulting in PDGFRA rearrangement, t(5;12) resulting in PDGFRB rearrangement, t(9;22) resulting in BCR/ABL1 rearrangement and chromosome 8 abnormalities resulting in FGFR1rearrangements. Although some of these chromosome abnormalities can be detected on routine chromosome analysis, FISH is more sensitive in identifying and accurately characterizing the underlying gene rearrangements and hence is the preferred method for diagnosis.
Methodology
Culture/Hybridization/Microscopy/Interpretation
The samples are usually cultured for 24 hours before hybridizing with the probes. After hybridization and post-hybridization washes, the slides are analyzed under a fluorescence microscope equipped with epifluorescence and appropriate filter sets. Analysis and scoring are carried out by two certified technologists in a blinded fashion. Results are reviewed by both the laboratory manager and the director.
Specimen Collection / Handling Requirements
This is a comprehensive panel that includes all the genes involved in myeloproliferative neoplasms/myelodysplastic diseases with or without eosinophilia. All these genetic markers, if abnormal, are responsive to treatment with tyrosine kinase inhibitors. This panel is also called in some literature as “Tyrosine Kinase Inhibitor Responsive Panel”.
Probe List
| MPN/MPD Panel | ||
| Probe Name | Locus/CHR | Catalogue # |
| FIP1L1,CHIC2,PDGFRA | 4q12 | Cytocell LPH032 |
| PDGFRB | 5q32 | Cytocell LPH031 |
| FGFR1/D8Z2 | 8p11.23-p11.22/8p11.1-q11.1 | Cytocell LPS018 |
| ASS1/ABL1/BCR | 9q34/22q11.2 | Cytocell LPH038 |
Minimum Specimen Requirements
Bone Marrow and/or Leukemia Blood
Container: Sodium Heparin (green top tube)
Optimal Quantity: 2-3 ml
Minimum Quantity: 1-2 ml
Storage: Room Temperature
Stability at Room Temperature: 8 hours, then refrigerate
Transportation: Avoid freezing or heating over 35°C
Turnaround time
Final report in 7-10 days
Communication
The morphologic interpretation and correlation of results on all cases is performed by a board-certified doctoral level scientist (laboratory director). The final report has a narrative description of results. If abnormalities are present, they are explained in a paragraph which helps to clarify and correlate chromosomal findings with phenotype. References are included in the report to help the referring physician with interpretation, which include books or journals that contain appropriate information. Recommendations are made as to any additional testing, if necessary.
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