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Mixed acute leukemia with genotypic lineage switch: a case report
S Ciolli1, F Leoni, R Caporale
1Division at Hematology, University of Florence, Italy.
Leukemia
|July 1, 1993
Summary
This study details a rare acute myeloid leukemia case that switched to a lymphoid phenotype, then back to myeloid. Genomic analysis revealed a consistent TCR delta gene rearrangement, suggesting an early pathogenetic event.
Area of Science:
- Hematology
- Oncology
- Genetics
Background:
- Leukemias typically present with distinct morphologic and phenotypic characteristics.
- Mixed-phenotype leukemias, while rare, present diagnostic and therapeutic challenges.
- Understanding phenotypic plasticity is crucial for leukemia management.
Observation:
- A case of acute myeloid leukemia (AML) initially co-expressed B-lymphoid markers.
- Upon relapse, the leukemia underwent a complete phenotypic and genotypic switch to a lymphoid form.
- Further relapse saw the re-emergence of myeloid features, retaining specific genomic rearrangements.
Findings:
- Immunoglobulin (Ig) H and T-cell receptor (TCR) gene analysis revealed germline configuration at diagnosis, with a TCR delta deletion.
- Monoclonal rearrangements of IgH, TCR tau, and TCR delta were detected at first relapse.
- Consistent TCR delta gene configuration across disease phases suggests an early pathogenetic event, deeming a second malignancy unlikely.
Implications:
- Phenotypic evolution in leukemia can be influenced by chemotherapy.
- Genomic alterations, particularly TCR delta gene configuration, can serve as lineage-independent markers.
- This case highlights the complex interplay between genotype, phenotype, and treatment response in leukemia.