Cytogenetics of multiple myeloma: interpretation of fluorescence in situ hybridization results

The cytogenetic picture in multiple myeloma (MM) is highly complex, from which non-random numerical and structural chromosomal changes have been identified. Specifically, translocations involving the immunoglobulin heavy chain gene (IGH) at 14q32 and either monosomy or deletions of chromosome 13 have been reported in a significant number of patients from both cytogenetic and interphase fluorescence in situ hybridization (FISH) studies. Importantly, these abnormalities of chromosome 13 have recently been associated with a poor prognosis. In view of the highly complex nature of the karyotypes in MM patients, interphase FISH results may be difficult to interpret. In this study, cytogenetics and/or interphase FISH were carried out on bone marrow samples or purified plasma cells from 37 MM patients. Abnormal karyotypes, characterized by multiplex FISH (M-FISH) were found in 11 patients, all of which were highly complex. Interphase FISH revealed translocations involving the IGH locus in 16 (43%) patients. The IGH/cyclin D1 (CCND1) gene fusion characteristic of the translocation, t(11;14)(q13;q32), was seen in 12 (32%) of these patients and other rearrangements of IGH in four (11%) patients. Fourteen patients had additional copies of chromosome 11. Twenty patients (54%) had 13q14 deletions, 10 of whom also had t(11;14) or another IGH translocation. By comparing cytogenetic and FISH results, this study has revealed that significant chromosomal abnormalities might be hidden within highly complex karyotypes. Therefore, extreme caution is required in the interpretation of interphase FISH results in MM, particularly in relation to certain abnormalities, such as 13q14 deletions, which have an impact on prognosis.     

Chromosome 13 abnormalities in multiple myeloma are mostly monosomy 13

Chromosome 13 abnormalities are frequently observed in multiple myeloma (MM). Several reports recently demonstrated the strong prognostic value of these abnormalities, associated with a short survival. Cytogenetic studies have shown that most of these abnormalities are complete monosomies. In order to define the common minimal deletion, we analysed a series of 234 patients with MM using fluorescence in situ hybridization (FISH) with a panel of five probes mapping along the whole chromosome 13. A chromosome 13 abnormality was observed in 98 patients (42%), 90 of whom (92%) displayed a complete monosomy. In seven of the eight remaining patients presenting partial deletions, the three probes specific for the 13q14 region were deleted. Only one patient (1%) displayed a small deletion of the D13S319 locus. In conclusion, FISH should be used for the analysis of chromosome 13 abnormalities, using probes mapping in the 13q14 region.     

Chronic lymphocytic leukaemia profiled for prognosis using a fluorescence in situ hybridisation panel

A panel of fluorescence in situ hybridisation (FISH) probes was used on 894 cases to target chromosome 11q, 13q, 17p deletions (del), trisomy 12 (+12) in all and 6q deletion in 59. Chronic lymphocytic leukaemia (CLL) immunophenotype (CD5 and CD19 with CD23) was found in 509 cases (average age 67.7 years, 319 males and 190 females). Among the 509 CLL cases 349 (68.6%) had FISH (4-probe panel) abnormalities: 160 del 13q [45.8% (122-del 13q, 18-biallelic del 13q, 20-monoallelic/biallelic del 13q)], 71 tri 12 (20.3%), 17 del ATM (5%), 12 del p53 (3.4%) and 89 > or = 2 FISH abnormalities (25.5%). Of 151/509 cases karyotyped, 108 were normal and 43 (43/151 = 28.5%) abnormal. Del 6q was found in 1/59 (1.6%) FISH cases and in 6/151 (4%) karyotypes. In 14 CD23 negative cases IGH/BCL1 FISH detected t(11;14) and was confirmed to be mantle cell lymphoma. Multiple probes/panels that included IGH probe were ordered for 57 CLL cases, 11 had an IGH rearrangement with an unidentified partner. This study favours the inclusion of del 6q and IGH probes in the CLL panel. The FISH panel could also serve to monitor 13q deletion for secondary changes with adverse prognosis. Understanding prognosis in specific types of 13q deletion would enhance outcome prediction.     

Long-term follow up with conventional cytogenetics and band 13q14 interphase/metaphase in situ hybridization monitoring in monoclonal gammopathies of undetermined significance

One-third of patients with monoclonal gammopathy of undetermined significance (MGUS) may progress to multiple myeloma (MM) and may develop a long arm deletion of chromosome 13 (13q-). As the incidence of 13q-, time of development and prognostic impact in MGUS patients is still under debate, we decided to perform serial sequential conventional cytogenetics (CC) and metaphase/interphase fluorescence in situ hybridization (FISH) analyses on bone marrow mononuclear cells obtained from 18 asymptomatic, untreated MGUS patients. Median follow up was 30 months (range 6-72). Interphase FISH identified a 13q14 deletion in five out of 18 patients (on clinical diagnosis in one patient and during the follow up in the remaining four patients). Subsequently, metaphase FISH and CC also identified the deletion in four out of five patients. All five of the patients progressed to MM 6-12 months after 13q- identification, without developing any FISH determined JH rearrangements. MM progression also occurred in two other karyotypically normal patients. We conclude that: (i) the extent of the 13q deletion does not vary during the clinical outcome; (ii)13q- plays a crucial role in MGUS/MM pathogenesis and confers a proliferative advantage to clonal plasma cells being initially demonstrated by interphase FISH and only afterwards by metaphase FISH and CC; and (iii) association of 13q- with t(4;14)(p16.3;q32) remains to be demonstrated. However, a transition from MGUS to MM may also occur in patients with normal karyotypes or other abnormalities, suggesting the possibility of distinct pathogenetic pathways.     

Deletion of 13q14 remains an independent adverse prognostic variable in multiple myeloma despite its frequent detection by interphase fluorescence in situ hybridization

Interphase fluorescence in situ hybridization (FISH) studies of chromosomal region 13q14 were performed to investigate the incidence and clinical importance of deletions in multiple myeloma (MM). Monoallelic deletions of the retinoblastoma-1 (rb-1) gene and the D13S319 locus were observed in 48 of 104 patients (46.2%) and in 28 of 72 (38.9%) patients, respectively, with newly diagnosed MM. FISH studies found that 13q14 was deleted in all 17 patients with karyotypic evidence of monosomy 13 or deletion of 13q but also in 9 of 19 patients with apparently normal karyotypes. Patients with a 13q14 deletion were more likely to have stage III disease (P =.022), higher serum levels of beta(2)-microglobulin (P =.059), and a higher percentage of bone marrow plasma cells (P =.085) than patients with a normal 13q14 status on FISH analysis. In patients with a deletion of 13q14, myeloma cell proliferation (Ki-67) was markedly increased (22.0% +/- 6.9% compared with 15.6% +/- 8.2% in patients without the deletion; P =.0008). Evaluation of bromodeoxyuridine incorporation in 5 patients revealed that both rb-1-deleted and rb-1-normal MM subpopulations were proliferative. The presence of a 13q14 deletion on FISH analysis was associated with a significantly lower rate of response to conventional-dose chemotherapy (40.8% compared with 78. 6%; P =.009) and a shorter overall survival (24.2 months compared with > 60 months; P <.005) than in patients without the deletion. Multivariate analysis of prognostic factors confirmed the independent predictive value of 13q14 deletions for shortened survival. In conclusion, deletions of 13q14 are frequently detected by interphase FISH in patients with newly diagnosed MM, correlate with increased proliferative activity, and represent an independent adverse prognostic feature in MM. (Blood. 2000;95:1925-1930)     

21例多发性骨髓瘤分子遗传学异常的FISH检测的意义

目的：为探讨间期荧光原位杂交（FISH）在检测多发性骨髓瘤（MM）间期细胞13q14缺失、1q21、p53缺失以及免疫球蛋白重链（IgH）基因重排中的意义。方法：采用组合探针（1q21/RB1、D13S319/p53、IgH）对21例MM患者骨髓进行FISH检测,分析其分子遗传学异常,比较其与常规染色体检查及临床指标的相关性。结果：21例MM患者中,19例（90.48%）检测出1种或1种以上的细胞遗传学异常,15例（71.43%）同时检测出2种及以上的异常。其异常比例从高到低分别为：＋1异常（66.67%）,IgH基因重排（57.14%）,13号染色体缺失（47.62%）和p53基因丢失（23.81%）。3例（14.29%）通过G-显带常规染色体检查发现异常,与FISH比较两者差异有统计学意义（P〈0.01）。结论：＋1、IgH基因重排及13q14缺失在MM中的发生率较高。FISH技术能提高MM分子遗传学异常的敏感性。     

Various patterns of IgH deletion identified by FISH using combined IgH and IgH/CCND1 probes in multiple myeloma and chronic lymphocytic leukemia

Introduction: Interphase fluorescence in situ hybridization (FISH) can identify submicroscopic deletions adjacent to the breakpoints of rearrangements undetected by conventional cytogenetics. In this study, the characteristics and frequency of the IgH deletion identified by interphase FISH were investigated in patients with multiple myeloma (MM) and chronic lymphocytic leukemia (CLL). Methods: The study group included 29 patients with MM and eight patients with CLL. Interphase FISH was performed with the IgH dual color, break‐apart rearrangement probe and the IgH/CCND1 dual color, dual fusion translocation probe. Results: The IgH deletion was found in 14% (4/29) of patients with MM and 13% (1/8) of the patients with CLL. Four patients had deletions of the whole or variable region of IgH on the native chromosome 14, whereas one patient had a deletion of the IgH variable region on a der(11)t(11;14). In two patients, the IgH break‐apart FISH showed both patterns with and without IgH deletions. In cases showing the same pattern by IgH break‐apart FISH, the IgH/CCND1 FISH showed different patterns, and vice versa. Conclusion: A variety of patterns of the IgH deletion were identified by interphase FISH using IgH break‐apart and IgH/CCND1 probes in patients with MM and CLL. The results of this study suggest that the integrated information obtained with IgH break‐apart and IgH/CCND1 FISH was needed to interpret FISH results unambiguously.     

Fluorescent in situ hybridization studies in multiple myeloma

Abstract

Conventional cytogenetic analysis and fluorescence in situ hybridization (FISH) results of bone marrow samples of 36 multiple myeloma (MM) patients at the time of diagnosis have been evaluated. Three probes for chromosome 13q (RB1, D13S319, D13S25), one for 14q32 (IgH) and one for 17p13 (p53) have been used for hybridization with fixed cells. Twenty patients (55·5%) had normal karyotypes, whereas eight (22·2%) had numerical or structural chromosomal abnormalities. We did not find metaphases for chromosome analysis in eight (22·2%) patients. Fluorescence in situ hybridization analyses revealed at least one or more abnormal results in 25 (69·5%) cases, whereas 11(30·5%) cases had no abnormal findings. 14q32 rearrangement was the most common finding in FISH analyses and has been detected in 21 cases (58·3%). 13q deletion and 17p deletion have been detected in 11 (30·5%) and 5 (13·9%) cases, respectively. Fluorescence in situ hybridization studies including 14q32 and 17p13 chromosome regions may yield quite significant results during clinical follow-up of MM.     

New insights into role of microenvironment in multiple myeloma

Multiple Myeloma (MM) is a malignant disease of terminally differentiated B cells. It most likely originates in a B cell which has traversed the germinal center and has been exposed there extensively to antigens based on the high number of somatic mutations in the complementarity determining regions. The cell of origin is either a plasmablast, or more likely, a memory B-cell. Typically MM goes through different phases from indolent (MGUS, smoldering myeloma) to overt myeloma and then to a fulminant phase, characterized by extramedullary manifestations, high LDH, immature morphology and increased proliferation rate. In the indolent phase, the disease already has acquired major cytogenetic abnormalities as demonstrated by FISH and DNA flow cytometry. It has a gene pattern very similar to myeloma cells on gene array analysis. In the early stages of overt MM, the myeloma cells are completely dependent upon the micro-environment for their growth and survival. The interaction between myeloma cells and micro-environment causes bone disease, genetic instability and more importantly, drug-resistance, which is caused by upregulation of anti-apoptotic factors, resistance to apoptosis induced by FAS and TRAIL activation, and by cell adhesion-induced growth arrest. In this phase of the disease, MM is susceptible to chemotherapy, if delivered with adequate intensity. In the fulminant phase of MM, myeloma cells have acquired sufficient genetic alternations to become completely independent of the micro-environment which allows them to grow at extramedullary sites. Because of the many DNA breaks necessary for immature B cells to become mature plasma cells, B cells already have inherent genetic instability. DNA breaks are necessary for VDJ recombinations, somatic mutations and isotype switching and it is therefore not surprising that genetic alternations frequently occur at the Ig heavy chain site at 14q32, which is abnormal in three quarters of myeloma patients. Some of the translocations with 14q32 involve terminal fragments of chromosomes and can not be diagnosed with standard cytogenetics. Cytogenetic abnormalities are found in 30-35% of newly diagnosed patients and require sufficient proliferation of MM cells to find enough analyzable mitoses. The cytogenetic abnormalities are typically complex, involving > or = 3 chromosomes in 80% of patients. Almost all chromosomes can be involved in deletions, additions or translocations of genetic material. Our group has repeatedly stressed the prognostic significance of chromosome 13 deletion by conventional cytogenetics. The role of chromosome 13 deletion by FISH. is less clear. In addition to chromosome 13 deletion, the presence of a hypodiploid or hypotetraploid karyotye also carries a poor prognosis. Frequently, deletions of chromosome 13 and hypodiploidy go hand in hand. It remains unclear what specific gene confers the poor prognosis to patients with deletion 13. The issues of bone disease, drug resistance and cytogenetics will be addressed in detail during this presentation.     

High frequencies of chromosomal aberrations in multiple myeloma and monoclonal gammopathy of undetermined significance in direct chromosome preparation

Although many cases of multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) are cytogenetically normal, interphase fluorescence in situ hybridization (FISH) analyses reveal aberrations in the majority of the cases. Most likely, non-neoplastic cells are more prone to divide in culture than neoplastic cells. Direct chromosome preparations (DCP) would be one way to circumvent this methodological problem. We have investigated 47 bone marrow samples from 39 patients by DCP. A median of 58 metaphases (range 9-158) was analysed per sample. Interphase FISH analyses using probes to detect IGH rearrangements, -13/13q-, +3, +7, and +11 were also performed. Abnormal karyotypes were detected in 15 (63%) of 24 MM and in 4 (50%) of eight MGUS/smouldering MM (SMM) cases that could be successfully cytogenetically analysed. Age, sex, or degree of bone marrow plasma cell (PC) infiltration did not influence the karyotypic patterns (P > 0.05). However, the frequencies of aberrant karyotypes varied in relation to the Colcemide concentrations used - 7% (30 ng/ml) versus 69% and 67% (100 and 200 ng/ml, respectively) (P = 0.01). Combining the G-banding and FISH results, abnormalities were detected in 29 of 31 (94%) MM and in six of eight (75%) MGUS/SMM patients. Thus, cytogenetic and FISH analyses after DCP using 100-200 ng Colcemide/ml identified aberrations in most MM/MGUS/SMM, irrespective of PC percentages.     

Both chromosome 13 abnormalities by metaphase cytogenetics and deletion of 13q by interphase FISH only are prognostically relevant in multiple myeloma

OBJECTIVES: Deletion of chromosome 13q [del(13q)] has emerged as a major adverse prognostic factor in multiple myeloma (MM). Del(13q) is detected two to three times more frequently by interphase fluorescence in situ hybridization (FISH) than by metaphase cytogenetics (CG). However, it has remained unclear whether or not del(13q) detected by FISH only provides the same prognostic information as its detection by CG. METHODS: We investigated the outcome of 118 consecutive patients with newly diagnosed MM who were studied by both CG and FISH (RB-1 and/or D13S319 probes). RESULTS: CG revealed informative MM karyotypes in 35 patients (29.7%), with monosomy 13/del(13q) in 16 of them. FISH was indicative for a del(13q) in 43 patients (36.4%). A del(13q) by FISH was present in all 16 patients with monosomy 13/del(13q) by CG and also in four of 19 patients with informative karyotypes and diploid chromosome 13. Furthermore, del(13q) was present by FISH in 23 of 84 patients with diploid/non-informative metaphases by CG. Overall survival of patients with monosomy 13/del(13q) by CG and of patients with del(13q) by FISH only was not significantly different (median, 35.2 months vs. 33.2 months, P = 0.58). In contrast, patients with diploid chromosome 13 by either technique experienced prolonged survival (median, 65.6 months). Presence of abnormal karyotypes was significantly associated with an increased Ki67 growth fraction. CONCLUSION: FISH of chromosome 13q adds prognostic information to that provided by CG. It is suggested to use FISH analysis in clinical trials if risk stratifications take into consideration the chromosome 13q status.     

Quantitative PCR: an alternative approach to detect common copy number alterations in multiple myeloma

Chromosome 1q gains and 13q deletions are common cytogenetic aberrations in multiple myeloma (MM) that confer a poor prognosis. There are several techniques for the targeted study of these alterations, but interphase fluorescence in situ hybridization (FISH) is the current gold standard. The aim of the present study was to validate quantitative PCR (qPCR) as an alternative to FISH studies in CD138+-enriched plasma cells (PCs) from MM patients at diagnosis. We analyzed 1q gains and 13q deletions by qPCR in 57 and 60 MM patients, respectively. qPCR applicability was 84 and 88% for 1q and 13q, respectively. The qPCR and FISH methods had a sensitivity and specificity of 88 and 71% for 1q gains, and 79 and 100% for 13q deletions. A second qPCR assay for each region was carried out to confirm the previous results. Paired qPCR (two assays) and FISH results were available from 53 MM patients: 26 for 1q amplification and 27 for 13q deletion. qPCR assays gave concordant results (qPCR-consistent) in 20 of the 26 (77%) 1q gains and 25 of the 27 (93%) 13q deletions. Considering only the consistent data, the overall concordance among qPCR and FISH was 85 and 100% for 1q gains and 13q deletions, respectively. Our results show a substantial agreement between qPCR and the gold standard FISH technique, indicating the potential of qPCR as an alternative approach, particularly when the starting material is too scarce or cells are too damaged to obtain accurate results from FISH studies.     

多发性骨髓瘤患者81例细胞及分子遗传学研究

目的 探讨多发性骨髓瘤(MM)患者遗传学特征,评价添加细胞因子及延长培养时间对MM染色体核型分析的影响和间期荧光原位杂交(FISH)检测RB1与P53基因缺失的意义.方法 采用骨髓24h短期培养和G显带技术对81例MM患者进行染色体核型分析,其中28例患者同时采用添加IL-6(终浓度10 μg/L)和重组粒-巨噬细胞集落刺激因子(GM-CSF,终浓度40 μg/L)的6d培养法后的G显带核型分析,31例患者采用间期FISH方法检测RB1与P53基因缺失.结果 81例患者中有75例患者有足够可供分析的中期分裂象,其中31例(41.3％)检出异常克隆.在31例检出染色体异常核型的患者中,单纯染色体数目异常4例(12.9％),单纯染色体结构异常11例(35.5％),染色体数目和结构异常同时存在16例(51.6％).28例患者同时采用两种培养方法对照研究结果显示,骨髓24h短期培养法异常克隆检出率为25.0％,添加细胞因子的6d延期培养法异常克隆检出率为51.9％ (P =0.026).31例患者间期FISH结果显示RB1基因缺失10例(32.3％),P53基因缺失11例(35.5％),5例患者RBI和P53基因均缺失.结论 MM染色体核型异常半数以上为染色体数目和结构异常同时存在,显带技术是遗传学检测的基础,添加细胞因子的长期培养法可提高显带技术的异常克隆检出率,间期FISH是一种检测MM患者骨髓瘤细胞基因缺失的敏感方法,具有临床应用价值.     

Chromosomal and genetic abnormalities in myeloma

Chromosomal translocations are a hallmark of lymphoid tumours. Multiple myeloma (MM) is a tumour of the plasma cell, the terminally differentiated B lymphoid cell. In recent years, a large number of chromosomal and genetic abnormalities have been detected in myeloma, the most prominent being chromosome 13q deletions and translocations affecting the immunoglobulin heavy chain (IgH) locus on chromosome 14q32. The latter involve a large array of chromosomal partners, from which multiple oncogenes have been proposed as candidates for dysregulation. In addition, a wide variety of changes including numerical aberrations, translocations involving loci other than the immunoglobulin genes, and aberrations of known oncogenes such as N-ras mutations, have been found. With the refinement of molecular cytogenetic techniques, the sensitivity of detecting these molecular abnormalities is continuing to increase. However, with the exception of 13q deletions which have been consistently associated with an adverse prognosis, the role of the other changes in the pathogenesis of MM, and their effect on disease behaviour and prognosis are still being clarified. In this review, we will discuss the most common molecular abnormalities found in primary MM and cell lines, and consider the available evidence for a pathogenic role in MM.     

Molecular cytogenetic aberrations in 21 Chinese patients with plasma cell leukemia

Plasma cell leukemia (PCL) is a rare malignant plasma cell disorder. Cytogenetic studies performed on plasma cell disorders are scarce and difficult because of the low proliferation rate of plasma cells (PCs). Fluorescence in situ hybridization (FISH) analysis is an attractive alternative for evaluation of chromosomal changes in PCL. To explore the molecular cytogenetic abnormalities in Chinese patients with PCL, interphase FISH studies with three probes for the regions containing 13q14.3 (D13S319), 14q32 (IGHC/IGHV) and 1q12(CEP1) were retrospectively performed in 21 PCL patients. FISH with LSI IGH/CCND1 and LSI IGH/FGFR3 probes were used to detect t(11;14)(q13;q32) and t(4;14)(p16;q32) in patients with 14q32 rearrangement. Among 21 PCL patients, molecular cytogenetic aberrations were found in 18 (81.8%) patients, four (19.0%) patients simultaneously had 13q14 deletion, illegitimate IgH translocation and 1q abnormality. 13q14 deletion was detected in 13 (61.9%) cases and illegitimate 14q32 rearrangement in 16 (76.2%) including six with t(11;14) and three with t(4;14). Chromosome 1 abnormality was found in seven (33.3%) patients, one with deletion of 1q, six with at least three copies amplifications of 1q12 (Amp1q12). 14q32 rearrangement and 13q14 deletion were found concurrently in 11 (52.4%) cases. It was showed that most PCL had chromosomal abnormalities, 14q32 rearrangement, 13q14 deletion and chromosome 1 abnormality are the frequent abnormalities, and over half of the 14q32 rearrangement were t(11;14) or t(4;14). t(4;14) and 13q14 deletion were correlated in PCL. FISH is a highly sensitive technique at detecting molecular cytogenetic aberrations in PCL and should be used in the routine evaluation of PCL.     

Value of comparative genomic hybridization and fluorescence in situ hybridization for molecular diagnostics in multiple myeloma

Chromosomal abnormalities, such as 13q deletions, are emerging as important prognostic factors in multiple myeloma. Fluorescence in situ hybridization (FISH) using specific DNA probes is the technique most widely used for the determination of genomic aberrations in this disease. The utility of comparative genomic hybridization (CGH) for molecular diagnostics in plasma cell malignancies has not been systematically analysed. We investigated tumour samples of patients with multiple myeloma (n = 43) or plasma cell leukaemia (n = 3) using CGH and FISH with five DNA probes localized to chromosome bands 1p22, 6q21, 11q22-q23, 13q14 and 17p13. By CGH, the most frequent genomic changes were gains on chromosomes 1q, 9q and 11q, as well as losses on chromosomes 13q, 6q, Xp and Xq. By FISH, trisomy 11q was identified at a similar frequency to the 13q deletion (42%). Compared with FISH data, the sensitivity of CGH was 80.7% and the specificity was 97.5%. Thirty-two aberrations found by FISH were not identified by CGH, mostly as a result of the proportion of cells carrying the respective aberrations, or because of the limited spatial resolution of CGH. Our data indicate that, for clinical molecular diagnostics in multiple myeloma, FISH with a disease-specific DNA probe set is superior to CGH analysis.     

The recurrent IgH translocations are highly associated with nonhyperdiploid variant multiple myeloma

Aneuploid is ubiquitous in multiple myeloma (MM), and 4 cytogenetic subcategories are recognized: hypodiploid (associated with a shorter survival), pseudodiploid, hyperdiploid, and near-tetraploid MM. The hypodiploid, pseudodiploid, and near-tetraploid karyotypes can be referred to as the nonhyperdiploid MM. Immunoglobulin heavy-chain (IgH) translocations are seen in 60% of patients. We studied the relation between aneuploidy and IgH translocations in MM. Eighty patients with MM and abnormal metaphases were studied by means of interphase fluorescent in situ hybridization (FISH) to detect IgH translocations. We also studied a second cohort of 199 patients (Eastern Cooperative Oncology Group [ECOG]) for IgH translocations, chromosome 13 monosomy/deletions (Delta13), and ploidy by DNA content. Mayo Clinic patients with abnormal karyotypes and FISH-detected IgH translocation were more likely to be nonhyperdiploid (89% versus 39%, P <.0001). Remarkably, 88% of tested patients with hypodiploidy (16 of 18) and 90% of tested patients with tetraploidy (9 of 10) had an IgH translocation. ECOG patients with IgH translocations were more likely to have nonhyperdiploid MM by DNA content (68% versus 21%, P <.001). This association was seen predominantly in patients with recurrent chromosome partners to the IgH translocation (11q13, 4p16, and 16q23). The classification of MM into hyperdiploidy and nonhyperdiploidy is dictated largely by the recurrent (primary) IgH translocations in the latter.     

多发性骨髓瘤患者13号染色体长臂部分缺失及其临床意义

目的研究多发性骨髓瘤（MM）患者13号染色体长臂特定位点的缺失及与临床表现、预后的关系。方法采用荧光原位杂交技术检测68例MM患者骨髓标本中Rb-1基因和13q14．3位点的缺失,结合临床资料作统计分析。结果13号染色体部分缺失的总检出率为51％（35／68）,其中Rb-1基因缺失43％（29／68）,13q14．3位点缺失为52％（23／44）,两位点同时缺失者66％（29／44）。卡方检验分析显示13号染色体部分缺失与患者起病时多种临床特征及早期疗效、1年生存率有关。结论Rb-1基因和13q14．3位点的缺失在MM中均较为常见,13号染色体部分缺失对MM的生物学行为有一定影响。     

Interphase Fluorescence In Situ Hybridization Detection of Cytogenetic Abnormalities in B-Cell Chronic Lymphocytic Leukemia

The most frequent chromosomal abnormalities in B-cell chronic lymphocytic leukemia (B-CLL) are deletions on 13q14 and 17p13, trisomy 12, and 14q32 rearrangement. Conventional cytogenetic analysis underestimates the frequency of specific chromosome aberrations in B-CLL because of the low rate of spontaneous mitoses and the poor response to mitogen stimulation. We used interphase fluorescence in situ hybridization (I-FISH) to explore the incidence of chromosomal changes in the peripheral blood cells of B-CLL patients. Probes for 13q14 (D13S319), 17p13 (p53), the centromere of chromosome 12 (CEP12), and 14q32 (IGHC/IGHV) were applied to detect chromosomal aberrations in peripheral blood samples from 83 B-CLL patients (60 men, 23 women). Molecular cytogenetic aberrations were found in 61 cases (73.5%), and 8 patients (9.6%) showed 2 kinds of abnormalities. The most frequent abnormality was deletion of 13q14 (41.0%), followed by +12 (19.3%), deletion of 17p13 (12%), and 14q32 rearrangement (9.6%). FISH results were analyzed for correlation with Binet stages. The percentages of patients who showed abnormalities by FISH were 73.0%, 73.3%, and 80% for Binet stages A, B, and C, respectively, and the percentages of patients with abnormalities who showed 2 anomalies were 7.9%, 27.3%, and 0% for Binet stages A, B, and C, respectively. We noted no consistent pattern among the various Binet stages in the distribution of either the types of FISH-detected anomalies or the numbers of FISH anomalies. I-FISH was found to be a rapid, exact, and sensitive technique for analysis of chromosome aberrations in CLL. FISH could provide accurate information regarding the molecular cytogenetic features of CLL.     

Genetic abnormalities in multiple myeloma: role in oncogenesis and impact on survival

PURPOSE: Recent development of interphase fluorescence in situ hybridization (FISH) allows analysis on non-proliferant plasma cells. We describe the most frequent genetic abnormalities in multiple myeloma and their prognostic value. CURRENT KNOWLEDGE AND KEY POINTS: Most frequent genetic abnormalities are illegitimate rearrangements involving the IGH gene at 14q32 (60% of patients), hyperdiploidy (50 to 60% of patients), chromosome 13 deletion (40 to -50% of patients), chromosome 1q gain (30 to -40% of patients) chromosome 17 deletion (10% of patients). Some of these genetics abnormalities are observed in monoclonal gammopathy of undetermined significance (MGUS), a pre-malignant state. t(4;14) and t(14;16) translocations and chromosome 17 deletion negatively impact the overall survival. Patients with these genomic aberrations should be treated with specific treatment. FUTURE PROSPECTS AND PROJECTS: Identification of genetic abnormalities is important for evaluation of prognosis and treatment protocol in multiple myeloma.