Marcucci G, Livak K J, Bi W, Strout M P, Bloomfield C D, Caligiuri M A
Department of Internal Medicine, Comprehensive Cancer Center at The Ohio State University, Columbus 43210, USA.
Leukemia. 1998 Sep;12(9):1482-9. doi: 10.1038/sj.leu.2401128.
The AML1/ETO fusion transcript can be detected by reverse transcription polymerase chain reaction (RT-PCR) in patients with t(8;21)-associated acute myeloid leukemia (AML) in long-term complete remission (CR). Quantitation of the amount of the fusion transcript during CR may therefore be more predictive of cure or relapse than a simple qualitative assessment. Real Time PCR, a fluorometric-based technique, allows simple and rapid quantitation of a target sequence during the extension phase of PCR amplification, in contrast to end-point quantitative methods. Six patients with t(8;21)(q22;q22) AML, who achieved CR were studied by Real Time RT-PCR at different time intervals following diagnosis and high-dose cytarabine and anthracycline-based induction therapy. Five patients had a diagnostic bone marrow (BM) sample available for molecular analysis. Each patient showed > or = 10(3) copies of the AML1/ETO fusion transcript at diagnosis, and each showed a 2- to 4-log decrease in copy number following successful induction chemotherapy. This is comparable to the log-fold reduction in leukemic blasts that is thought to occur in patients successfully cytoreduced into CR by induction chemotherapy. The sixth patient showed a relatively high copy number immediately following successful remission induction chemotherapy, which continued to increase during early CR and was later followed by relapse. Real Time RT-PCR appears to offer advantages over previously used quantitative RT-PCR methods by providing absolute quantitation of the target sequence, expanding the dynamic range of quantitation to over six orders of magnitude, eliminating the post-PCR processing, and reducing labor and carryover contamination. These features make this an attractive method to prospectively evaluate the prognostic value of AML1/ETO fusion transcript quantitation in a larger patient population with t(8;21)(q22;q22) AML in CR.
通过逆转录聚合酶链反应（RT-PCR）可在处于长期完全缓解（CR）的t(8;21)相关急性髓系白血病（AML）患者中检测到AML1/ETO融合转录本。因此，在CR期间对融合转录本数量进行定量分析可能比简单的定性评估更能预测治愈或复发情况。与终点定量方法不同，实时PCR是一种基于荧光的技术，可在PCR扩增的延伸阶段对目标序列进行简单快速的定量分析。对6例t(8;21)(q22;q22) AML且达到CR的患者，在诊断及大剂量阿糖胞苷和蒽环类药物诱导治疗后的不同时间间隔，采用实时RT-PCR进行研究。5例患者有可用于分子分析的诊断性骨髓（BM）样本。每位患者在诊断时均显示≥10³份AML1/ETO融合转录本，且在成功诱导化疗后，每位患者的拷贝数均下降了2至4个对数级。这与成功通过诱导化疗使白血病原始细胞数量减少的患者中所认为的对数级降低程度相当。第6例患者在成功诱导缓解化疗后即刻显示相对较高的拷贝数，在CR早期持续增加，随后复发。实时RT-PCR似乎比先前使用的定量RT-PCR方法具有优势，它能对目标序列进行绝对定量，将定量动态范围扩大到超过六个数量级，无需PCR后处理，减少了工作量和交叉污染。这些特性使其成为一种有吸引力的方法，可在前瞻性评估更大规模处于CR的t(8;21)(q22;q22) AML患者群体中AML1/ETO融合转录本定量分析的预后价值。
