The translocation t(8;21)(q22;q22) is one of the most frequent chromosomal abnormalities associated with acute myeloid leukemia (AML) sub type M2. About 3–5 % of cases with additional chromosomal abnormalities, including structural and numerical ones, are reported to include a complex translocation t(8;21;N). Here we report a chromosome rearrangement observed in a 19 years-old female diagnosed with AML-M2. When subjected to (molecular) cytogenetic analyses a complex three-way translocation involving chromosomes 8, 17 and 21 was detected, forming not a t(8;21;17) as one would expect. Real time-polymerase chain reaction analysis using 6 AML specific markers showed the presence of RUNX1/RUNX1T1 fusion gene transcripts identical to those found in classical translocation t(8;21) coupled with presence of FLT3-ITD mutation identified by fragment analysis. The present case highlights importance of complex rearrangements rarely encountered in AML, suggesting that all involved regions harbor critical candidate genes regulating the pathogenesis of AML, leading to novel as well as well-known leukemia associated chromosomal aberrations.

中文翻译：

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带有染色体8、17和21的RUNX1 / RUNX1T1融合的急性髓样白血病M2中的复杂重排

易位t（8; 21）（q22; q22）是与M2亚型急性髓细胞白血病相关的最常见染色体异常之一。据报道，约有3-5％的其他染色体异常病例，包括结构和数字异常，包括复杂的易位t（8; 21; N）。在这里，我们报告了在一名19岁的被诊断患有AML-M2的女性中观察到的染色体重排。进行（分子）细胞遗传学分析时，检测到涉及染色体8、17和21的复杂三向易位，未如人们预期的那样形成at（8; 21; 17）。实时聚合酶链反应分析使用6种AML特异性标记，显示RUNX1 / RUNX1T1融合基因转录本的存在与经典易位t（8; 21）中发现的转录本相同，并且存在通过片段分析鉴定的FLT3-ITD突变。