Link-Lenczowska Dorota, Sacha Tomasz, Zawada Magdalena, Czekalska Sylwia, Florek Izabela, Skotnicki Aleksander B
Przegl Lek. 2014;71(5):258-62.
More than 95% of patients with detected translocation t(9;22), is characterized by the fusion between exons e13 or e14 of BCR gene, which are located in major breakpoint cluster region (M-bcr) and exon a2 of ABL gene. These fusions are described as b2a2 (e13a2) and b3a2 (e14a2). Other fusions of exons e1, e6, e8, e12, e19, e20 of BCR gene with exons a2 or a3 of ABL gene occur very rarely and lead to formation of so called unusual fusion BCR-ABL genes. The aim of this study is to describe long-term observations of the occurrence and routine procedure in the diagnosis of atypical variants of the fusion gene BCR-ABL in a population of patients with chronic myeloid leukemia (CML). It was found that the vast majority of patients with detected BCR-ABL transcripts were b3a2 and b2a2. Other detected variants, which are described as rare were: e1a2, b2a3, b3a3, c3a2, e6a2, e6a3. At the stage of diagnosis as well as during monitoring of the effects of treatment, molecular methods which are based on polymerase chain reaction were used (multiplex RT-PCR, nested RT-PCR, RQ-PCR). Multiplex RT-PCR reaction gave possibility to detect variants of the fusion BCR-ABL gene in one reaction and was crucial in the selection of appropriate test used for further monitoring of the disease and the effectiveness of treatment. This paper proposes a scheme for dealing with the diagnosis and monitoring of minimal residual disease (MRD) in patients with CML treated with tyrosine kinase inhibitors (TKIs) in the presence of rare fusion of the BCR and ABL genes.
在检测到易位t(9;22)的患者中，超过95%的患者其特征是位于主要断裂点簇区域（M-bcr）的BCR基因外显子e13或e14与ABL基因外显子a2之间发生融合。这些融合被描述为b2a2（e13a2）和b3a2（e14a2）。BCR基因的外显子e1、e6、e8、e12、e19、e20与ABL基因的外显子a2或a3的其他融合非常罕见，会导致形成所谓的异常融合BCR-ABL基因。本研究的目的是描述慢性髓性白血病（CML）患者群体中融合基因BCR-ABL非典型变体的发生情况及诊断常规程序的长期观察结果。研究发现，检测到BCR-ABL转录本的绝大多数患者为b3a2和b2a2。其他检测到的被描述为罕见的变体有：e1a2、b2a3、b3a3、c3a2、e6a2、e6a3。在诊断阶段以及治疗效果监测期间，使用了基于聚合酶链反应的分子方法（多重逆转录聚合酶链反应、巢式逆转录聚合酶链反应、实时定量逆转录聚合酶链反应）。多重逆转录聚合酶链反应能够在一次反应中检测融合BCR-ABL基因的变体，对于选择用于进一步监测疾病和治疗效果的合适检测方法至关重要。本文提出了一种在存在BCR和ABL基因罕见融合的情况下，对接受酪氨酸激酶抑制剂（TKIs）治疗的CML患者进行微小残留病（MRD）诊断和监测的方案。
