Onozawa Masahiro, Fukuhara Takashi, Nigo Motohiko, Takeda Akinori, Takahata Mutsumi, Yamamoto Yasushi, Miyake Takayoshi, Kanda Makoto, Maekawa Isao
Department of Internal Medicine, Asahikawa City Hospital 1-65, Kinseicho 1 chome, Asahikawa, Hokkaido, Japan.
Cancer Genet Cytogenet. 2003 Dec;147(2):134-9. doi: 10.1016/s0165-4608(03)00199-7.
A 43-year-old man was diagnosed with acute myelocytic leukemia with cellular maturation (AML-M2, according to the French-American-British classification criteria). A cytogenetic study with a G-banding method initially reported the karyotype as 45,X,-Y; however, dual-color, dual-fusion fluorescence in situ hybridization (FISH) with probes for the AML1 and the ETO genes showed an unusual pattern of signals, presenting one fusion signal on chromosome 21. Molecular study by reverse transcriptase polymerase chain reaction revealed the presence of a typical AML1/ETO chimeric gene. FISH with whole-chromosome painting probes targeting chromosomes 8 and 21 revealed insertion of part of 8 chromosome into the long arm of chromosome 21. We concluded that complicated translocations involving chromosomes 8 and 21 in this patient resulted in the development of the chimeric gene, AML1/ETO, on the long arm of chromosome 21. This aberrant location of AML1/ETO gene and the final karyotype of 45,X,-Y,ins(21;8)(q22;q22q22) could not be determined without molecular analysis. This abnormality is considered a masked t(8;21).
一名43岁男性被诊断为伴有细胞成熟的急性髓细胞白血病（根据法美英分类标准为AML-M2）。最初采用G显带法进行的细胞遗传学研究报告其核型为45,X,-Y；然而，使用针对AML1和ETO基因的探针进行的双色、双融合荧光原位杂交（FISH）显示出异常的信号模式，在21号染色体上呈现出一个融合信号。通过逆转录聚合酶链反应进行的分子研究揭示了典型的AML1/ETO嵌合基因的存在。使用靶向8号和21号染色体的全染色体涂染探针进行的FISH显示8号染色体的一部分插入到了21号染色体的长臂中。我们得出结论，该患者中涉及8号和21号染色体的复杂易位导致了21号染色体长臂上嵌合基因AML1/ETO的形成。若不进行分子分析，无法确定AML1/ETO基因的这种异常定位以及最终核型45,X,-Y,ins(21;8)(q22;q22q22)。这种异常被认为是隐匿性t(8;21)。
