Shao J, Zhang L, Semenza J C, Beach B, Smith M T
School of Public Health, University of California, Berkeley 94720-7360, USA.
Cancer Genet Cytogenet. 1996 Dec;92(2):135-40. doi: 10.1016/s0165-4608(96)00181-1.
Tetrasomy 8 is a rare clonal anomaly in human acute leukemia. Here we present a case of a 7-year-old boy with acute lymphoblastic leukemia (ALL) displaying a tetrasomy 8 clone that could not be detected by conventional cytogenetics. In this study, bone marrow and peripheral blood cells were collected at five different diagnostic stages and analyzed by double targeted fluorescence in situ hybridization (FISH) with centromeric DNA probes for chromosomes 7, 8, 9, and 12. FISH analysis revealed a significant increase in tetrasomy 8 frequency, but not in other chromosomes examined. A smaller increase in trisomy 8 was also detected. At one stage over 60% of the cells were hyperdiploid with 40% being tetrasomic. The size of the tetrasomic clone changed during the course of the disease. The hyperdiploid frequencies of chromosome 8 detected by interphase FISH analysis in bone marrow and peripheral blood were similar. Our findings indicate the utility of FISH analysis in cytogenetic monitoring of leukemia patients and further show that tetrasomy 8 may play a specific role in a subtype of ALL.
8号染色体四体是人类急性白血病中一种罕见的克隆性异常。本文报告一例7岁急性淋巴细胞白血病（ALL）男孩病例，其存在一个常规细胞遗传学方法无法检测到的8号染色体四体克隆。在本研究中，在五个不同诊断阶段采集骨髓和外周血细胞，并用针对7号、8号、9号和12号染色体的着丝粒DNA探针进行双靶向荧光原位杂交（FISH）分析。FISH分析显示8号染色体四体频率显著增加，但其他检测染色体未见此现象。同时也检测到8号染色体三体有较小幅度增加。在某一阶段，超过60%的细胞为超二倍体，其中40%为四体。四体克隆的大小在疾病过程中发生变化。通过间期FISH分析检测到的骨髓和外周血中8号染色体超二倍体频率相似。我们的研究结果表明FISH分析在白血病患者细胞遗传学监测中的实用性，并进一步表明8号染色体四体可能在ALL的一个亚型中发挥特定作用。
