Intrachromosomal amplification of RUNX1 gene on chromosome 21 (iAMP21) is a rare occurrence in acute myeloid leukemia (AML). Herein, we describe a case of AML with amplification of RUNX1 and its insertion on chromosome 2 detected by conventional karyotyping and confirmed by metaphase FISH. A six-year-old female was diagnosed as acute myeloid leukemia with monocytic differentiation. The patient's bone marrow revealed 74% blasts which were MPO negative. Conventional karyotyping revealed a complex karyotype, with rearrangements in chromosomes 1, 2, 7, 8 and hsr(21). FISH on interphase cells with LSI RUNX1-RUNX1T1 dual colour dual fusion translocation probe showed 6-7 copies of RUNX1 signal. Metaphase FISH with LSI RUNX1-RUNX1T1 probe confirmed amplification of RUNX1 and insertion of amplified RUNX1 sequences on long arm of chromosome 2. Induction chemotherapy was initiated, however, the patient died within one month of diagnosis suggesting poor outcome associated with this novel finding. Insertion of amplified RUNX1 on another chromosome has not yet been reported so far.

21 号染色体上RUNX1基因的染色体内扩增(iAMP21) 在急性髓系白血病 (AML) 中很少发生。在此，我们描述了一个 AML 病例，其中RUNX1扩增并通过常规核型分析检测到其插入 2 号染色体，并通过中期 FISH 确认。一名 6 岁女性被诊断为单核细胞分化的急性髓性白血病。患者的骨髓显示 74% 的原始细胞为 MPO 阴性。传统的核型分析揭示了一种复杂的核型，在染色体 1、2、7、8 和 hsr(21) 中发生了重排。具有 LSI RUNX1-RUNX1T1 双色双融合易位探针的间期细胞上的 FISH 显示 6-7 个RUNX1信号拷贝。带有 LSI RUNX1-RUNX1T1 探针的中期 FISH 证实了RUNX1和在 2 号染色体长臂上插入扩增的RUNX1序列。开始诱导化疗，然而，患者在诊断后一个月内死亡，表明与这一新发现相关的不良结果。迄今为止，尚未报道在另一条染色体上插入扩增的RUNX1。