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Cytogenetically cryptic PML::RARA fusion in acute promyelocytic leukemia: Testing strategies in the modern era
Kirill Karlin1, Christine Bryke1, Ajoy Dias2
1Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA, United States of America.
Abstract:
Acute promyelocytic leukemia (APL) is a unique leukemia that is characterized by the PML::RARA fusion. This fusion is often detected by conventional karyotype and fluorescence in situ hybridization (FISH); however, rare cases are cryptic and require molecular techniques to identify the PML::RARA fusion. Furthermore, as the incidence of these cases is rare, analysis by a targeted next-generation sequencing (NGS) panel of myeloid associated genes has never been reported. Herein, a clinical APL case is reported where the PML::RARA fusion was detected only by reverse transcriptase-polymerase chain reaction (RT-PCR), thus underscoring the necessity of utilizing complementary techniques when suspicion for APL is present.
Insights
Acute promyelocytic leukemia (APL) requires molecular testing for cryptic PML::RARA fusions. This case highlights the importance of reverse transcriptase-polymerase chain reaction (RT-PCR) for accurate APL diagnosis.
Area of Science:
- Hematology
- Molecular Diagnostics
- Oncology
Background:
- Acute promyelocytic leukemia (APL) is a distinct subtype of leukemia.
- It is characterized by the specific PML::RARA fusion gene.
- Conventional cytogenetic methods like karyotype and FISH often detect this fusion.
Observation:
- Rare cases of APL present with cryptic PML::RARA fusions.
- These cryptic fusions may not be identified by standard cytogenetic analyses.
- Targeted next-generation sequencing (NGS) panels for myeloid genes have not been reported for such rare cases.
Findings:
- A clinical case of APL is presented where the PML::RARA fusion was exclusively detected by reverse transcriptase-polymerase chain reaction (RT-PCR).
- This molecular technique proved essential when conventional methods failed to identify the fusion.
- The study emphasizes the limitations of standard diagnostic approaches in rare APL scenarios.
Implications:
- The findings underscore the necessity of employing complementary molecular techniques, such as RT-PCR, in suspected APL cases.
- Accurate and timely diagnosis of APL is crucial for appropriate treatment initiation.
- This case highlights the value of molecular diagnostics in identifying rare genetic abnormalities in hematologic malignancies.
