Acute Lymphocytic Leukemia (ALL) – Ph Extended Panel
CPT Code(s)
88271x10, 88275x10
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
Acute lymphoblastic/lymphocytic leukemia (ALL) is the most common hematological malignancy seen in children. A large number of specific chromosome abnormalities and/or gene rearrangements are seen in patients with ALL with the incidence of such abnormalities ranging from 65-85% for adults and 60-70% for children. Detection of these abnormalities is vital in stratification of patients into different treatment groups, and it is now mandatory to carry out chromosome and FISH studies, especially in children, for enrollment into Children’s Oncology Group (COG) treatment protocols. Although majority of such abnormalities can be detected on routine chromosome analysis, interphase FISH analysis due to its high sensitivity can detect low-level clones thus identifying prognostically and therapeutically important genetic abnormalities.
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 the extensive ALL panel with all most all known and frequent genetic abnormalities included.
Probe List
| ALL – Extended | ||
| Probe Name | Locus/CHR | Catalogue # |
| FIP1L1/CHIC2/PDGFRA | 4q12 | Cytocell LPH032 |
| MYC | 8q24.21 | Cytocell LPH010 |
| CDKN2A/D9Z3 | 9p21.3/9q12 | Cytocell LPH009 |
| ASS1/ABL1/BCR | 9q34/22q11.2 | Cytocell LPH038 |
| D10Z1/D17Z1 | Chromosomes 10/17 | Cytocell LPE010G/LPE017R |
| KMT2A | 11q23.3 | Cytocell LPH013 |
| ETV6/RUNX1 | 12p13.2/21q22.12 | Cytocell LPH012 |
| IGH | 14q32.33 | Cytocell LPH014 |
| TCF3 | 19p13.3 | Cytocell LPH019 |
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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