Cuneo A, Bigoni R, Roberti M G, Bardi A, Rigolin G M, Piva N, Mancini M, Nanni M, Alimena G, Mecucci C, Matteucci C, La Starza R, Bernasconi P, Cavigliano P, Genini E, Zaccaria A, Testoni N, Carboni C, Castoldi G
Institute of Hematology, University of Ferrara, Italy.
Haematologica. 1998 Jan;83(1):21-6.
The role of fluorescence in situ hybridization (FISH) in the detection and monitoring of trisomy 8 (+8) in acute myelogenous leukemia (AML) has not been defined exactly. This multicentric study was performed in order to: i) analyze the sensitivity of interphase FISH with respect to conventional chromosome analysis (CCA) in detecting +8; ii) compare the results of FISH and CCA in the quantitation of the frequency of +8-positive cells; iii) analyze the possible role of FISH in the cytogenetic follow-up of patients with +8.
One hundred and ninety-eight nonconsecutive patients with a diagnosis of AML seen at five centers over a 3-year period were studied by CCA and FISH with a chromosome 8-specific centromeric probe. Two hundred interphase cells were scored in each test and the cut-off for the recognition of +8 was set at 3%. An irrelevant pericentromeric probe was used as negative control in those cases with an apparently normal karyotype and trisomy 8 in interphase cells. FISH studies were conducted at diagnosis and, in 14 cases with +8, on 1.5 occasions during follow-up.
Karyotype aberrations were seen in 121 cases (61.1%), with +8 being present in 38 of them (16 as the sole aberration). Interphase FISH detected +8 in 37/38 cases; in a patient with 1/10 metaphases with +8, 2.3% interphase cells with 3 signals were seen. Fourteen additional cases with occult +8 were detected by FISH, which showed 4-22% interphase cells with three signals; 6 patients had an abnormal karyotype without +8, 3 had a normal karyotype, 5 had no analyzable mitoses. In 24 cases with > 15 analyzable metaphases, percent variations between CCA and FISH in the estimation of the size of the trisomic clone ranged between 0.4% and 51%, median value 22%. Underestimation of the percent of trisomy 8 by FISH occurred in all 10 cases with > 90% +8 metaphases. In 7/14 cases investigated sequentially, FISH detected 5-35% trisomic cells in the BM after induction therapy (4 CR, 3 PR); 4 cases relapsed with +8 at 8-15 months. The absence of +8 in remission marrows was documented in the remaining 7 cases, 4 of which relapsed at 20-32 months.
It is concluded that FISH was a valuable method in this multicentric study since it showed greater sensitivity than CCA in detecting minor clones with +8, in patients with both normal and abnormal karyotypes. The role of FISH in the cytogenetic follow-up of trisomies in AML patients may be promising.
荧光原位杂交（FISH）在急性髓系白血病（AML）中8号染色体三体（+8）检测及监测方面的作用尚未完全明确。开展这项多中心研究的目的是：i）分析间期FISH在检测+8方面相对于传统染色体分析（CCA）的敏感性；ii）比较FISH和CCA在定量+8阳性细胞频率方面的结果；iii）分析FISH在+8患者细胞遗传学随访中的可能作用。
对5个中心在3年期间诊断为AML的198例非连续患者进行了CCA和使用8号染色体特异性着丝粒探针的FISH研究。每次检测对200个间期细胞进行评分，将识别+8的临界值设定为3%。对于核型明显正常且间期细胞存在8号染色体三体的病例，使用无关的着丝粒周围探针作为阴性对照。FISH研究在诊断时进行，对于14例存在+8的病例，在随访期间进行1.5次检测。
121例（61.1%）出现核型异常，其中38例存在+8（16例为唯一异常）。间期FISH在38例中的37例检测到+8；在1例1/10个中期细胞存在+8的患者中，观察到2.3%的间期细胞有3个信号。FISH又检测出另外14例隐匿性+8病例，这些病例显示4 - 22%的间期细胞有3个信号；6例患者核型异常但无+8，3例核型正常，5例无可用以分析的有丝分裂细胞。在24例有>15个可分析中期细胞的病例中，CCA和FISH在估计三体克隆大小方面的百分比差异在0.4%至51%之间，中位数为22%。在所有10例+8中期细胞比例 > 90%的病例中，FISH均低估了8号染色体三体的百分比。在14例进行序贯研究的病例中，7例在诱导治疗后FISH检测到骨髓中5 - 35%的三体细胞（4例完全缓解，3例部分缓解）；4例在8 - 15个月时复发且伴有+8。其余7例缓解期骨髓中未检测到+8，其中4例在20 - 32个月时复发。
得出结论，在这项多中心研究中，FISH是一种有价值的方法，因为它在检测核型正常和异常患者中含+8的小克隆方面比CCA具有更高的敏感性。FISH在AML患者三体细胞遗传学随访中的作用可能很有前景。
