Qin Ya-zhen, Liu Yan-rong, Li Jin-lan, Wang Hui, Chang Yan, Fu Jia-yu, Ruan Guo-rui, Shi Hui-lin, Qiu Jing-ying, Lu Dao-pei, Chen Shan-shan
Institute of Hematology, People's Hospital of Peking University, Beijing 100044, China.
Zhonghua Xue Ye Xue Za Zhi. 2004 Jul;25(7):409-12.
To investigate the unusual bcr/abl fusion gene structures of two Ph chromosome positive chronic myelogenous leukemia (CML) patients in chronic phase (CP).
By using general M- and micro -bcr/abl specific primers respectively, bcr/abl fusion transcripts were detected by reverse transcription-polymerase chain reaction (RT-PCR). The RT-PCR products sequencing was performed, the DNA sequences were analyzed in Genebank and the bcr and abl sequences at the fusion site were identified. DNA was amplified by PCR using a set of primers designed according to the sequencing result of RT-PCR products.
Two patients showed typical manifestations of CML-CP. Their RT-PCR products were different from usual M- or micro -type; one was longer than M-bcr/abl but shorter than micro -bcr/abl, the other one was shorter than M-bcr/abl. The RT-PCR products sequencing showed that both products contained bcr and abl gene sequences. The first patient's bcr gene was broken within exon 18, and fused to abl gene exon 2(a2), and a 40 bp of partial abl intron 1b fragment was inserted between them, resulting in a novel in-frame bcr/abl fusion transcript-e18-int-a2 which has not been reported in the literature so far. In the second patient, deletion of abl exon2(a2) led to exon 13(b2) of bcr gene fusing with abl exon 3(a3).
Uncommon bcr/abl fusion gene may occur in typical Ph(+) CML patient.
研究2例处于慢性期（CP）的Ph染色体阳性慢性髓性白血病（CML）患者异常的bcr/abl融合基因结构。
分别使用通用的M-bcr/abl和微bcr/abl特异性引物，通过逆转录聚合酶链反应（RT-PCR）检测bcr/abl融合转录本。对RT-PCR产物进行测序，在基因库中分析DNA序列并鉴定融合位点的bcr和abl序列。根据RT-PCR产物的测序结果设计一组引物，通过PCR扩增DNA。
2例患者均表现出CML-CP的典型症状。他们的RT-PCR产物不同于常见的M型或微小型；一个比M-bcr/abl长但比微bcr/abl短，另一个比M-bcr/abl短。RT-PCR产物测序表明，两种产物均包含bcr和abl基因序列。首例患者的bcr基因在第18外显子内断裂，与abl基因第2外显子（a2）融合，二者之间插入了一段40 bp的abl内含子1b部分片段，形成了一种新的读框内bcr/abl融合转录本-e18-int-a2，该转录本迄今未见文献报道。在第二例患者中，abl外显子2（a2）缺失导致bcr基因第13外显子（b2）与abl外显子3（a3）融合。
典型的Ph（+）CML患者可能出现罕见的bcr/abl融合基因。
