Sessarego M, Fugazza G, Balleari E, Bruzzone R, Ballestrero A, Patrone F
Department of Internal Medicine, D.I.M.I., University of Genoa, Italy.
Cancer Genet Cytogenet. 1997 Sep;97(2):161-4. doi: 10.1016/s0165-4608(96)00323-8.
Correct diagnosis of acute promyelocytic leukemia (APL) requires proof of the translocation (15;17)(q24;q11), which appears to be absolutely specific for this particular type of myeloid disorder. We studied the karyotypes of 29 consecutive APL patients at diagnosis: in 5 of them banding techniques failed to detect the t(15;17). In these seemingly cytogenetically negative cases, fluorescence in situ hybridization (FISH) with a chromosome 17 painting probe detected a high percentage of mitoses with 3 hybridization signals: one derived from the intact chromosome 17, and 2 from the rearranged chromosomes 15 and 17. Trisomy 8 (+8) as a secondary chromosomal abnormality was observed in 8 cases (27.5%), confirming that the t(15;17) favors the acquisition of an extra chromosome 8. One of these 8 cases showed a marker that was interpreted by FISH analysis as der(8) with duplication of a segment of the long arm carrying the c-MYC allele. Clinical features of patients with t(15;17) and +8 were no different from patients with t(15;17) alone. The usefulness of FISH to standard banding techniques in the detection of specific structural and/or numerical chromosomal abnormalities is confirmed in this report.
急性早幼粒细胞白血病（APL）的正确诊断需要证实存在易位（15；17）（q24；q11），这似乎是这种特定类型髓系疾病的绝对特异性特征。我们研究了29例连续APL患者诊断时的核型：其中5例采用显带技术未能检测到t（15；17）。在这些看似细胞遗传学阴性的病例中，使用17号染色体涂染探针进行荧光原位杂交（FISH）检测到高比例的有丝分裂具有3个杂交信号：一个来自完整的17号染色体，另外两个来自重排的15号和17号染色体。8例（27.5%）观察到8号染色体三体（+8）作为继发性染色体异常，证实t（15；17）有利于额外获得一条8号染色体。这8例中的1例显示一个标记，FISH分析将其解释为der（8），伴有携带c-MYC等位基因的长臂片段重复。t（15；17）和+8患者的临床特征与单纯t（15；17）患者无异。本报告证实了FISH相对于标准显带技术在检测特定结构和/或数量染色体异常方面的实用性。
