Hochhaus A, Reiter A, Skladny H, Melo J V, Sick C, Berger U, Guo J Q, Arlinghaus R B, Hehlmann R, Goldman J M, Cross N C
III. Medizinische Klinik, Klinikum Mannheim der Universität Heidelberg, Mannheim, Germany.
Blood. 1996 Sep 15;88(6):2236-40.
A novel variant of the chimeric BCR-ABL mRNA transcript was detected in a patient with Philadelphia chromosome-negative (Ph-) chronic myelogenous leukemia (CML) by multiplex reverse-transcription polymerase chain reaction (RT-PCR). Sequence analysis of the fusion region of the amplified cDNA fragment showed an in-frame joining of exon e6 of the BCR gene and exon a2 of the ABL gene, giving rise to an e6a2 BCR-ABL transcript. This finding was confirmed by Southern blot analysis using a specific probe corresponding to intron 6 of the BCR gene, whereas conventional Southern blot for rearrangement of the major breakpoint cluster region (M-bcr) was negative. Western blot studies detected a BCR-ABL protein slightly larger than p185 BCR-ABL. Metaphase fluorescence in situ hybridization showed an insertion of ABL material into the BCR region without reciprocal BCR translocation. The findings in this case show that atypical BCR-ABL transcripts are detectable even in Ph- CML patients without M-bcr-rearrangements. Multiplex PCR using primers that allow for amplification of all known BCR-ABL transcripts is an appropriate method to exclude these rare variants.
通过多重逆转录聚合酶链反应（RT-PCR）在一名费城染色体阴性（Ph-）慢性粒细胞白血病（CML）患者中检测到一种嵌合型BCR-ABL mRNA转录本的新型变体。对扩增的cDNA片段融合区域的序列分析显示，BCR基因的外显子e6与ABL基因的外显子a2发生了读码框内连接，产生了一种e6a2 BCR-ABL转录本。使用对应于BCR基因内含子6的特异性探针进行Southern印迹分析证实了这一发现，而用于主要断裂点簇集区域（M-bcr）重排的传统Southern印迹检测为阴性。蛋白质印迹研究检测到一种比p185 BCR-ABL略大的BCR-ABL蛋白。中期荧光原位杂交显示ABL物质插入BCR区域，而没有BCR的相互易位。该病例的研究结果表明，即使在没有M-bcr重排的Ph- CML患者中也可检测到非典型BCR-ABL转录本。使用能够扩增所有已知BCR-ABL转录本的引物进行多重PCR是排除这些罕见变体的合适方法。
