A novel five-way complex translocation t(9;10;15;21;22)(q34;p11.2;q22;q22;q11.2) in a Chronic myeloid leukemia patient

<p><strong>Background:</strong> The BCR::ABL1 gene fusion is the hallmark of chronic myeloid leukemia (CML). Variant Philadelphia chromosome (Ph)-positive cases with complex chromosomal rearrangements involving additional chromosomes occur in 4-11% of c ases, but their prognostic significance remains unclear.</p> <p><strong>Methods:</strong> A 20-year-old male presenting with leukocytosis and anemia was evaluated using conventional<br />cytogenetics, fluorescence in situ hybridization (FISH), and reverse transcription PCR (RT-PCR) to identify chromosomal abnormalities and BCR::ABL1 transcript type.</p> <p><br /><strong>Results:</strong> Cytogenetic analysis revealed a novel balanced five-way translocation: 46,XY,t(9;10;15;21;22)<br />(q34;p11.2;q22;q22;q11.2). FISH confirmed the BCR::ABL1 fusion in 97% of nuclei, and RT-PCR detected the<br />e13a2 (p210) BCR::ABL1 transcript. The patient exhibited rapid progression to blast crisis and resistance to<br />first-line imatinib therapy.</p> <p><br /><strong>Conclusion:</strong> This novel five-way translocation in Ph-positive CML highlights the importance of comprehensive<br />cytogenetic and molecular characterization to detect rare variants that may influence treatment response and<br />prognosis.</p>