INTERPHASE DETECTION OF GENE REARRANGEMENTS SPECIFIC TO NON-HODGKIN'S LYMPHOMA USING DOUBLE-COLOR FISH

染色体易位涉及免疫球蛋白重链（lgH）基因14q32.3及其伴侣基因与b细胞恶性肿瘤的发病机制和临床特征密切相关。为了确定14q32.3易位与特定癌基因位点的实际发生率，我们采用双色荧光原位杂交（DC-FISH）分析了173例b细胞非霍奇金淋巴瘤（NHL）患者。DC-FISH使用lgH基因（14q32.3）联合c-MYC （8q24.1）、BCL1（11q13.3）、BCL2（18q21.3）、BCL6（3q27）和PAX-5（9p13）基因探针检测173例患者中70例（40.5%）的lgH易位。70例患者中有56例（80%）发现了与lgH易位相关的伴侣基因：56例患者中有52例检测到lgH基因和癌基因探针的融合，特别是在29例患者的间期细胞核中，细胞遗传学分析没有提供信息。最常见的伴侣基因是BCL2, 19例（占总患者的11%），其次是BCL1 11例（6%），c-MYC 7例（4%），PAX-5 2例（1%）。在其余4例患者中，伴侣分别为19q13 (BCL3), 6p25 (MUM1/IRF4)， 1q36和8号染色体。3例患者发现lgH基因双易位。在所有病例中，lgH易位的一个伙伴是c-MYC，另一个伙伴分别是BCL1、BCL2和BCL6基因，提示lgH基因参与了B-NHL的发病和进展的多步骤过程。此外，我们克隆了一例MALT淋巴瘤患者的MALT1基因，并利用YAC克隆建立了检测t特异性易位的FISH方法（11;18）。39例B-NHL患者中有4例检测到t(11; 18)， 12例原发性巨球蛋白血症患者中有1例检测到t（11; 18）。使用淋巴瘤特异性易位探针的间期FISH可以建立一种新的B-NHL患者分类和预测预后。

Chromosomal translocation involving the immunoglobulin heavy chain (lgH) gene at band 14q32.3 and its partner genes are closely associated with both the pathogenesis and clinical characteristics of B-cell malignancies. To define the actual incidence of 14q32.3 translocation with specific oncogene loci, we analyzed 173 patients with B-cell non-Hodgkin's lymphoma (NHL) by double-color fluorescence in situ hybridization (DC-FISH). DC-FISH using the lgH gene (14q32.3) in combination with c-MYC (8q24.1), BCL1(11q13.3), BCL2(18q21.3), BCL6(3q27), and PAX-5(9p13) gene probes detected lgH translocations in 70 (40.5%) of 173 patients. The partner genes involved in lgH translocation were identified 56 (80%) of 70 patients : a fusion of the lgH gene and oncogene probes were detected in 52 of 56 patients, particularly on interphase nuclei of 29 patients, in whom cytogenetic analysis was not informative. The most common partner gene was BCL2 in 19 patients (11% of total patients), followed by BCL1 in 11 (6%), c-MYC in 7 (4%), and PAX-5 in 2 (1%). In the remaining 4 patients the partners were 19q13 (BCL3), 6p25 (MUM1/IRF4), 1q36, and chromosome 8 in one each. Double translocation of the lgH gene was found in 3 patients. In all of them one of the partners of lgH translocation was c-MYC, and the other partner was BCL1, BCL2, and BCL6 gene, respectively, suggesting the multistep process of the lgH gene involvement implicated in the pathogenesis and progression of B-NHL. Furthermore, we cloned MALT1 gene in a patient with MALT lymphoma, and established a FISH method to detect the specific translocation of t(11 ; 18) using YAC clonesw. The t(11 ; 18) was detected in 4 of 39 patients with B-NHL and one of 12 patient with primary macroglobulinemia. Interphase FISH with lymphoma-specific translocation probes warrants establishing a novel classification and predicting outcome of patients with B-NHL.