Reciprocal Translocation — oncology-focused definition
A reciprocal translocation is a chromosomal abnormality in which segments from two non-homologous chromosomes are exchanged, without a net loss or gain of genetic material (usually).
Key points in oncology:
- Can lead to oncogene activation or fusion gene formation if breakpoints occur within or near genes.
- Often balanced, meaning no genetic material is lost, but gene function may still be disrupted.
- Common mechanism for cancer-driving translocations, especially in hematologic malignancies.
Examples
| Translocation | Fusion Gene | Cancer |
|---|---|---|
| t(9;22) | BCR–ABL1 | CML, Ph+ ALL |
| t(8;14) | MYC–IgH | Burkitt lymphoma |
| t(15;17) | PML–RARA | APL |
| t(11;14) | CCND1–IgH | Mantle cell lymphoma |
Clinical significance (for oncology pharmacists):
- Diagnostic: Detection of reciprocal translocations confirms specific leukemias or lymphomas.
- Therapeutic: Some create targetable fusion proteins (e.g., BCR–ABL1 → TKIs; PML–RARA → ATRA).
- Prognostic: Presence of specific reciprocal translocations can indicate aggressive disease or better response to therapy.
Key takeaway:
A reciprocal translocation is a two-way chromosomal swap that can create oncogenic fusion genes, serving as diagnostic, prognostic, and therapeutic markers in oncology.
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