Fujii Fumiaki, Nojima Shingo, Matsuoka Satomi, Kakinoki Yasutaka
Department of Hematology, Asahikawa City Hospital.
Rinsho Ketsueki. 2023;64(7):626-632. doi: 10.11406/rinketsu.64.626.
Double minute chromosomes (dmin) are small, acentric, and extrachromosomal fragments that frequently mediate oncogene amplification and induce rapid disease progression with poor prognosis, although they are infrequent in myeloid neoplasms. An 81-year-old woman with anemia and thrombocytopenia was admitted to our hospital. Bone marrow examination showed 54.0% of the blasts. She was diagnosed with acute myeloid leukemia (French-American-British classification, M2; World Health Organization classification, acute myeloid leukemia [AML], not otherwise specified, AML with maturation). Chromosomal analysis revealed the presence of 3-45 dmin in the background of 46 and XX in 14 out of 20 metaphases examined. Spectral karyotyping examination demonstrated that the dmins were derived from chromosome 8. Fluorescence in situ hybridization (FISH) targeting the MYC gene demonstrated that dmins contained full-length MYC genes with multiple signals. Finally, she was diagnosed with AML with dmin via MYC amplification and was administered with venetoclax plus azacitidine chemotherapy. After two cycles of the regimen, FISH found no MYC amplification signals, indicating her state being in cytogenetic remission. At present, she has finished four cycles of the regimen and remained in complete remission. Venetoclax plus azacitidine could be an effective regimen for the poor prognosis of AML with dmin through MYC amplification.
双微体染色体(dmin)是小的、无着丝粒的染色体外片段,尽管在髓系肿瘤中不常见,但它们常介导癌基因扩增并导致疾病快速进展,预后不良。一名81岁贫血和血小板减少的女性入住我院。骨髓检查显示原始细胞占54.0%。她被诊断为急性髓系白血病(法美英分类,M2;世界卫生组织分类,急性髓系白血病[AML],未另行指定,伴成熟的AML)。染色体分析显示,在检测的20个中期细胞中,有14个中期细胞的背景为46,XX,存在3 - 45个双微体染色体。光谱核型分析检查表明,双微体染色体来源于8号染色体。针对MYC基因的荧光原位杂交(FISH)显示,双微体染色体包含具有多个信号的全长MYC基因。最后,她被诊断为通过MYC扩增的伴双微体染色体的AML,并接受了维奈克拉加阿扎胞苷化疗。经过两个周期的治疗方案后,FISH未发现MYC扩增信号,表明她处于细胞遗传学缓解状态。目前,她已完成四个周期的治疗方案,仍处于完全缓解状态。维奈克拉加阿扎胞苷可能是一种对通过MYC扩增的伴双微体染色体的AML预后不良有效的治疗方案。