Zelenetz A D, Chu G, Galili N, Bangs C D, Horning S J, Donlon T A, Cleary M L, Levy R
Department of Medicine, Stanford Medical School, CA.
Blood. 1991 Sep 15;78(6):1552-60.
The t(14;18) chromosomal translocation that results in the juxtaposition of the bcl-2 proto-oncogene with the heavy chain JH locus is a common cytogenetic abnormality in human lymphoma. In particular, it is seen in about 85% of follicular lymphoma (FL) and up to one-third of diffuse lymphomas (DL). The chromosome 18 breakpoints have been shown to cluster into two regions. The major breakpoint region (mbr) within the 3' untranslated region of the bcl-2 proto-oncogene accounts for approximately 60% of the cases and the minor cluster region (mcr) 30 kb 3' of bcl-2 accounts for approximately 25% of the breakpoints. Because of variability in the position of the breakpoint, detection of the t(14;18) by Southern blot analysis provides an important clonal marker for the tumor. However, conventional electrophoresis (CE) fails to detect the translocation in 15% to 25% of cases. We have applied pulsed-field gel electrophoresis (PFGE) to the detection of the t(14;18) in a series of lymphoma prospectively analyzed by CE, polymerase chain reaction (PCR), and cytogenetic analysis. PFGE readily detected t(14;18) rearrangements as indicated by comigration of bands detected with probes for the mbr region (chromosome 18) and the JH locus (chromosome 14). In a series of 40 patients with FL, this method proved to be the most comprehensive for detection of the translocation compared with standard methods; in fact, in one case only PFGE was able to detect the chromosomal rearrangement. Ten percent of the FL cases were negative by all methods tested. In a separate analysis of matched tissue specimens from cases of tumor progression of FL to diffuse lymphoma, PFGE detected a common t(14;18) rearrangement confirming a clonal origin in seven of seven cases, whereas CE detected a rearrangement in only three of seven cases. Overall, PFGE was able to detect a translocation in 8 of 12 cases that were negative by CE and four of eight negative by cytogenetic analysis. In conclusion, PFGE analysis is more comprehensive than CE, PCR, and cytogenetic analysis for the detection of the t(14;18) breakpoint in tissue biopsies of malignant lymphoma.
导致bcl-2原癌基因与重链JH基因座并列的t(14;18)染色体易位是人类淋巴瘤中常见的细胞遗传学异常。特别是，在约85%的滤泡性淋巴瘤（FL）和高达三分之一的弥漫性淋巴瘤（DL）中可见。18号染色体的断点已被证明聚集在两个区域。bcl-2原癌基因3'非翻译区内的主要断点区域（mbr）约占病例的60%，bcl-2下游30 kb的次要聚类区域（mcr）约占断点的25%。由于断点位置的变异性，通过Southern印迹分析检测t(14;18)可为肿瘤提供重要的克隆标记。然而，传统电泳（CE）在15%至25%的病例中未能检测到这种易位。我们将脉冲场凝胶电泳（PFGE）应用于一系列淋巴瘤中t(14;18)的检测，这些淋巴瘤通过CE、聚合酶链反应（PCR）和细胞遗传学分析进行前瞻性分析。PFGE很容易检测到t(14;18)重排，表现为用mbr区域（18号染色体）和JH基因座（14号染色体）探针检测到的条带共迁移。在一系列40例FL患者中，与标准方法相比，该方法被证明是检测易位最全面的方法；事实上，在1例中只有PFGE能够检测到染色体重排。10%的FL病例通过所有测试方法均为阴性。在对FL进展为弥漫性淋巴瘤病例的匹配组织标本进行的单独分析中，PFGE在7例中的7例中检测到常见的t(14;18)重排，证实了克隆起源，而CE仅在7例中的3例中检测到重排。总体而言，PFGE能够在CE检测为阴性的12例中的8例以及细胞遗传学分析检测为阴性的8例中的4例中检测到易位。总之，对于恶性淋巴瘤组织活检中t(14;18)断点的检测，PFGE分析比CE、PCR和细胞遗传学分析更全面。
