Objective To establish a real - time fluorescent quantitative reverse transcription - polymerase chain reaction(qRT - PCR) for detection of TEL - AML1 fusion gene mRNA in acute lymphoblastic leukemia ( ALL) children and explore its clinical significance. Methods A qRT-PCR with a TaqMan fluorescence probe and 2-△△et relative quantitative method was used to dynamically detect the expression levels of TEL - AML1 fusion gene in 20 acute lymphoblastic leukemia children with TEL - AML1 fusion gene positive at the time of newly diagnosed (n =20) ,complete remission (n =20) ,recurrence period (n =2) ,and 15 children with normal bone marrow morphology and with non tumor and no blood disease as a control group. Results Median of the expression level of TEL - AML1 fusion gene at newly diagnosed, complete remission, relapse period were 0. 62,0. 31,0.76,0. 23,respectively,and there were significant differences (Pa <0.05). The expression levels of TEL - AML1 gene in newly diagnosed and relapsed children were significantly higher than those of the children with remission and the control group( Pa <0.05). The expression levels of TEL - AML1 gene showed no significant difference between newly diagnosed and relapsed patients (P > 0. 05). The recurrence rate and event - free survival rate of patients with high level of TEL - AML1 expression ( > P75 of the control group) on day 33 were significantly higher and lower than those of low expression of children, respectively (P < 0. 05). Twenty patients on day 33 at the end of the first induction therapy achieved completely remission by bone marrow morphological examination. After intense and maintenance therapy, the high levels of the 8 children were declined. But the level of 1 case out of 8 cases abnormally increased and then the patient relapsed during maintenance therapy. After 2 months of ending chemotherapy, another 1 patient also relapsed with high TEL - AML1 level again. The levels of minimal residual disease were positive in 8 cases by qRT - PCR test, negative in 20 cases by bone marrow morphology and karyotype analysis tests, positive in 5 cases by real - time reaverse transcription - PCR test. Conclusions qRT - PCR is a rapid, efficient, sensitive and specific method. The expression level of TEL - AML1 gene on day 33 during induction of remission can be used for early prognosis. The changes of TEL - AML1 levels can be used to monitor minimal residual disease, prediction of relapse and guide individual treatment.%目的 建立实时荧光定量反转录(qRT)-PCR方法检测小儿急性淋巴细胞白血病TEL-AML1融合基因的表达水平,探讨其临床意义.方法 采用TaqMan探针qRT-PCR技术,2-△△et相对定量法动态检测20例TEL-AML1融合基因阳性急性淋巴细胞白血病患儿初诊期(20例)、缓解期(20例)、复发期(2例),及15例骨髓形态学正常的非肿瘤非血液病儿童作为对照组的TEL-AML1融合基因表达水平.结果 初诊期、缓解期、复发期及对照组的TEL-AML1中位数表达水平分别为0.62、0.31、0.76、0.23,初诊期和复发期基因表达水平均显著高于缓解期及对照组(Pa＜0.05),初诊期和复发期的表达水平比较差异无统计学意义(P＞0.05).诱导缓解第33天TEL-AML1水平高表达(＞对照组的P75)患儿的复发率、无病生存率期间显著高于和低于低表达患儿(Pa＜0.05).20例患儿首次诱导治疗第33天骨髓均达完全缓解,高表达8例均在强化治疗、维持治疗后TEL-AML1水平下降,但其中l例患儿在维持治疗期间TEL-AML1水平又异常升高后复发,另1例患儿在停药后2个月TEL-AML1水平再上升后复发.诱导缓解第33天qRT-PCR检测8例微小残留病阳性,骨髓形态学、染色体核型分析均阴性,实时反转录-PCR检测5例阳性.结论 qRT-PCR是一种快速、灵敏度高、特异性好的方法,诱导缓解第33天TEL-AML1融合基因水平可用于早期判断预后,TEL-AML1水平的变化可用于监测微小残留病、预测复发,指导个体化治疗.
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