20例非经典t(15;17)易位的急性早幼粒细胞白血病患者的分子遗传学分析

Molecular genetic analysis of unclassical t( 15; 17) translocations in 20 patients with acute promyelocytic leukemia

目的研究非经典t(15;17)易位包括不伴有t(15;17)易位及t(15;17)伴复杂异常的急性早幼粒细胞白血病(APL)患者的基因学变化,促进临床合理治疗方案选择。方法采用短期培养法R显带核型分析,荧光原位杂交(FISH)和逆转录-聚合酶链反应(RT-PCR)分析PML/RARA融合基因及分子学类型;流式细胞仪检测白血病免疫表型。结果 20例非经典t(15;17)易位患者中不伴有t(15;17)易位及t(15;17)伴复杂异常各10例。不伴有t(15;17)易位患者核型分析9例正常、1例为三体8;FISH分析PML/RARA融合基因仅1例阳性;RT-PCR方法检测4例1型(即L型)PML/RARA融合基因阳性、6例三型均阴性。t(15;17)伴复杂异常患者核型分析涉及t(15;17)的变异易位2例、等臂17q 1例、复杂易位5例、t(14;17)易位1例、t(5;17)易位1例;FISH分析8例阳性,RARA断裂点分离且PML/RARA融合基因阴性2例。结论经典t(15;17)易位,核型分析和FISH检测PML/RARA融合基因较为敏感;非经典t(15;17)易位,PML/RARA融合基因应结合核型分析、FISH、RT-PCR进行同时检测,且有助于检出FISH阴性RT-PCR方法阳性患者。

Objective To study the genetic variations of patients with non-classical t（ 15; 17） translocation,including translocation without t（ 15; 17） and translocation with complex and abnormal t（ 15; 17）,in acute promyelocytic leukemia（ APL） and promote the selection of clinically reasonable treatment options. Methods By adopting R banded karyotype analysis after short time culture,fluorescence in situ hybridization（ FISH） and reverse transcription-polymerase chain reaction（ RT-PCR） were conducted for the analysis of PML/RARA fusion gene and molecular type; flow cytometry was used to detect leukemia immune phenotype. Results Among the 20 patients with non-classical t（ 15; 17） translocations,there were 10 cases of translocation without t（ 15; 17） and t（ 15; 17） translocation with complicated abnormalities. The karyotype analysis of patients without t（ 15;17） translocation was normal in 9 cases and trisomy 8 in 1 case; FISH analysis revealed that only 1 case of PML/RARA fusion gene was positive; RT-PCR method detected 4 cases of type 1（ L Type） PML/RARA fusion gene,and 6 cases of type 3 were negative. The karyotype analysis of t（ 15; 17） patients with complicated abnormalities included 2 cases of t（ 15; 17） variant translocation,1 case of equal arm 17 q,5 cases of complex translocation,and 1 case of t（ 14; 17） translocation and 1 case of t（ 5; 17） translocation; FISH analysis revealed 8 cases were positive,RARA breakpoint isolation and PML/RARA fusion gene were negative in 2 cases. Conclusion The classic t（ 15; 17） translocation,karyotype analysis and FISH detection are more sensitive to the detection of PML/RARA fusion gene; non-classical t（ 15; 17） translocation,PML/RARA fusion gene should be combined with karyotype analysis,FISH,RT-PCR for simultaneous detection,which is helpful to the detection of patients with negative FISH results and positive RT-PCR results.