Yarkoni S, Lishner M, Tangi I, Nagler A, Lorberboum-Galski H
Department of Cellular Biochemistry, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
J Natl Cancer Inst. 1996 Jul 17;88(14):973-9. doi: 10.1093/jnci/88.14.973.
B cells of patients with non-Hodgkin's lymphoma (B-NHL) harbor specific chromosomal translocations, including t(14;18), the most common aberration found in this disease. The translocation involves the immunoglobulin (Ig) heavy-chain joining (JH) region gene on chromosome 14 and the BCL2 gene on chromosome 18, resulting in dysregulated expression of the BCL2 gene. The t(14;18) translocation has been thought to occur in the pre-B-cell stage, during the first event of Ig gene rearrangement.
This study was conducted to investigate the potential involvement of nonlymphoid lineages in B-NHL.
We studied the t(14;18) translocation and other frequently occurring translocations in total bone marrow aspirates of 10 patients with B-NHL, with the use of the fluorescence in situ hybridization (FISH) technique. We also performed cytogenetic analyses on representative bone marrow aspirates from the patients. Moreover, to define which of the major cell lineages present in the bone marrow carry the t(14;18) translocation, we used a series of monoclonal antibodies together with fluorescence-activated cell sorter (FACS) analyses to purify cells positive for CD3 (T cells), CD19 (B cells), CD10 (CALLA-positive cells), CD41a (megakaryocytic cells), CD13 (myeloid cells), and glycophorin A (erythroid cells). The cells of each subgroup underwent FISH analysis with the use of JH and BCL2 probes to detect the t(14;18) translocation. Bone marrow samples obtained from five healthy donors served as controls.
Bone marrow cells from eight of the 10 patients studied carried the t(14;18) translocation. When present, the translocation was observed in many or even all of the cell lineages (lymphoid, myeloid, megakaryocytic, and erythroid) present in the bone marrow, including peripheral blood progenitor stem cells; for seven of the eight patients carrying the translocation, it was found in 96%-100% of the unfractionated bone marrow cells as well as in all of the FACS-purified cell fractions in which it could be detected or studied. Conventional cytogenetic analyses performed on representative bone marrow aspirates confirmed the results obtained by FISH analysis. Cells in control bone marrow samples obtained from the five healthy donors were negative for the t(14;18) translocation by FISH analysis.
Our findings indicate that the t(14;18) translocation most probably occurs in a very early multilineage progenitor stem cell.
Given that the t(14;18) chromosomal translocation was found in all types of bone marrow cells when only the B cells were malignant, our results suggest that this translocation is not sufficient to induce neoplastic transformation. This finding underscores the need for the development of new approaches for the detection and surveillance of B-NHL.
非霍奇金淋巴瘤（B-NHL）患者的B细胞存在特定的染色体易位，包括t(14;18)，这是该疾病中最常见的畸变。这种易位涉及14号染色体上的免疫球蛋白（Ig）重链连接（JH）区域基因和18号染色体上的BCL2基因，导致BCL2基因表达失调。t(14;18)易位被认为发生在前B细胞阶段，即Ig基因重排的首次事件期间。
本研究旨在调查非淋巴谱系在B-NHL中的潜在参与情况。
我们使用荧光原位杂交（FISH）技术研究了10例B-NHL患者全骨髓抽吸物中的t(14;18)易位及其他常见易位。我们还对患者的代表性骨髓抽吸物进行了细胞遗传学分析。此外，为了确定骨髓中存在的主要细胞谱系中哪些携带t(14;18)易位，我们使用了一系列单克隆抗体以及荧光激活细胞分选仪（FACS）分析来纯化CD3阳性（T细胞）、CD19阳性（B细胞）、CD10阳性（CALLA阳性细胞）、CD41a阳性（巨核细胞）、CD13阳性（髓细胞）和血型糖蛋白A阳性（红细胞）的细胞。每个亚组的细胞使用JH和BCL2探针进行FISH分析，以检测t(14;18)易位。从5名健康供体获得的骨髓样本用作对照。
研究的10例患者中有8例的骨髓细胞携带t(14;18)易位。当存在易位时，在骨髓中存在的许多甚至所有细胞谱系（淋巴、髓、巨核和红系）中都观察到了易位，包括外周血祖干细胞；在8例携带易位的患者中有7例，在96%-100%的未分离骨髓细胞以及所有可检测或研究的FACS纯化细胞组分中都发现了易位。对代表性骨髓抽吸物进行的传统细胞遗传学分析证实了FISH分析的结果。通过FISH分析，从5名健康供体获得的对照骨髓样本中的细胞t(14;18)易位为阴性。
我们的研究结果表明，t(14;18)易位很可能发生在非常早期的多谱系祖干细胞中。
鉴于仅B细胞为恶性时在所有类型的骨髓细胞中都发现了t(14;18)染色体易位，我们的结果表明这种易位不足以诱导肿瘤转化。这一发现强调了开发新的B-NHL检测和监测方法的必要性。
