Fusionpositive

Fusionpositive is a term used in medical genetics and oncology to describe cells or tumors that carry a gene fusion resulting from chromosomal rearrangements. Gene fusions create chimeric transcripts and proteins that can drive oncogenesis. Fusionpositive tumors are identified by molecular diagnostic methods such as fluorescence in situ hybridization (FISH), reverse transcription-polymerase chain reaction (RT-PCR), and targeted next-generation sequencing.

Common examples of fusion events in human cancers include BCR-ABL in chronic myeloid leukemia, EWSR1-FLI1 in Ewing sarcoma, and PML-RARA in acute promyelocytic leukemia; these illustrate the broader category of fusionpositive cancers, though not all fusions are clinically actionable.

Clinical significance: Some fusion proteins are oncogenic and sustain tumor growth, making them targets for therapy. Treatments may include tyrosine kinase inhibitors (e.g., imatinib for BCR-ABL), or other fusion-targeted strategies. The prognosis and treatment approach for fusionpositive tumors depend on the specific fusion, tumor type, stage, and patient factors.

Limitations and challenges: Fusion detection can be technically challenging, and some tumors harbor multiple or cryptic fusions. Not all fusions confer sensitivity to targeted therapies, and resistance can develop.

Origin and usage: The phrase fusionpositive has emerged from discussions of molecular pathology and precision oncology to emphasize the role of fusion genes in tumor biology. It is not a formal disease classification but a descriptive label used in research and clinical reporting.

See also: Gene fusion, fusion oncogenes, targeted therapy, FISH, RT-PCR, next-generation sequencing.