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FISH for Pre-implantation Genetic Diagnosis
Published on: February 24, 2011
Probes for hidden hyperdiploidy in acute lymphoblastic leukaemia
A V Moorman1, R Clark, D M Farrell
1Haematology Department, Royal Free Hospital School of Medicine, London, United Kingdom.
Genes, Chromosomes & Cancer
|May 1, 1996
Summary
Detecting hyperdiploidy in acute lymphoblastic leukemia (ALL) is crucial for prognosis. A new fluorescence in situ hybridization (FISH) strategy accurately identifies high hyperdiploid (HeH) and low hyperdiploid (HeL) subgroups.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Hyperdiploidy, defined as clones with >46 chromosomes, significantly impacts prognosis in acute lymphoblastic leukemia (ALL).
- ALL patients are stratified into high hyperdiploid (HeH: 51-68 chromosomes), low hyperdiploid (HeL: 47-50 chromosomes), and triploid/tetraploid (TT: >68 chromosomes) subgroups, each associated with distinct outcomes.
- Accurate detection and subclassification of hyperdiploidy are essential for effective patient management.
Purpose of the Study:
- To develop and validate a fluorescence in situ hybridization (FISH) strategy for detecting and subtyping hyperdiploidy in acute lymphoblastic leukemia (ALL).
- To assess the efficiency of a stepwise FISH approach utilizing specific chromosome probes for accurate ploidy classification.
- To evaluate the utility of this FISH strategy in identifying hyperdiploid cases missed by conventional cytogenetics.
Main Methods:
- A stepwise fluorescence in situ hybridization (FISH) strategy employing chromosome-specific probes was developed.
- Ten specific chromosomes (X, 4, 6, 8, 10, 14, 16, 18, 20, and 21) were utilized in combinations to detect hyperdiploidy in interphase cells.
- The strategy was validated using a model population of 252 ALL cases and subsequently confirmed with 250 published karyotypes.
Main Results:
- The developed FISH strategy successfully detected 94% of hyperdiploid cases.
- Accurate prediction of the specific ploidy subgroup (HeH, HeL, TT) was achieved in 96% of detected hyperdiploid cases.
- The method required the application of four to six probes across two to three steps for each case.
Conclusions:
- This FISH-based strategy provides a reliable and efficient method for detecting and classifying hyperdiploidy in ALL.
- The approach demonstrates high accuracy in identifying hyperdiploid cases and their respective prognostic subgroups.
- This strategy is valuable for uncovering "hidden" hyperdiploid cases, particularly in patients with failed or normal conventional cytogenetics, thereby improving diagnostic yield and prognostic assessment.
