High incidence of chromosome 13 deletion in multiple myeloma detected by multiprobe interphase FISH

Multiple myeloma (MM) is a hypoproliferative malignancy yielding informative karyotypes in no more than 30% of newly diagnosed cases. Although cytogenetic and molecular deletion of chromosome 13 is associated with poor prognosis, a MM tumor suppressor gene (TSG) has not been identified. To localize a minimal deleted region of chromosome 13, clonotypic plasma cells from 50 consecutive patients with MM were subjected to interphase fluorescence in situ hybridization (FISH) analysis using a panel of 11 probes spanning the entire long arm of chromosome 13. Whereas chromosome 13 abnormalities were absent in plasma cells from 25 normal donors, 86% of patients with MM demonstrated such aberrations. Heterogeneity, both in deletion frequency and extent, was confirmed by simultaneous FISH with 2 chromosome 13 probes. Deletion hot spots were noted at D13S272 (70%) and D13S31 (64%), 2 unlinked loci at 13q14. Homozygous deletions at these loci occurred in 12% (simultaneously in 8%) of the cases. Molecular deletions were found in all 14 patients with morphologic deletions, in 21 of 24 with uninformative karyotypes, and 8 of 12 patients with karyotype abnormalities lacking chromosome 13 deletion. Homozygous deletion of any marker was noted in 4% with low and in 36% with higher plasma cell labeling index greater than 0. 4% (P =.01). The absence of increasing deletion incidence and extent with therapy duration suggests that the observed lesions are not induced by treatment. The high incidence and extent of chromosome 13 deletions require the correlation of specific deletion(s) with poor prognosis. These analyses will provide valuable guidance toward cloning of an MM-TSG. (Blood. 2000;96:1505-1511)     

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。     

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)     

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.     

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.     

Detection of 13q abnormalities in multiple myeloma using immunomagnetically selected plasma cells

Accurate prognostic evaluation of patients with multiple myeloma (MM) is required for their stratification for more adequate therapy. Chromosomal G-banding and interphase fluorescence in situ hybridization (FISH) on cell-nonspecific samples and on myeloma cells selected by magnetic-activated cell separation (MACS) were used to study 13 samples from 12 multiple myeloma (MM) patients. Bone marrow (BM) samples were analysed using three approaches. Standard mitotic samples were prepared and analysed after G-banding. Interphase FISH was performed to detect the 13q14 deletion in unselected BM cells. In parallel, myeloma cells were selected from the BM using the CD138-specific antibody. The high-purity myeloma cell suspension was then analysed by interphase FISH for the 13q14 deletion. Magnetic separation yielded enriched myeloma cell suspensions with the mean viability of 98.0% (range: 97.0%-99.0%), and the purity of 97.6% (range: 87.2%-99.2%) as detected morphologically, and 85.2% (range: 44.8%-98.4%) as detected by immunophenotyping for CD138+ cells. Interphase FISH revealed the 13q14.3 deletion in 5 of 13 (38.5%) of cell-nonspecific samples and in 9 of 13 (69.2%) of enriched myeloma cell suspensions. In conclusion, interphase FISH on immunomagnetically selected MM cells increases the detection of the 13q14 deletion in BM samples from the patients with MM.     

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.     

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.     

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.     

Molecular Cytogenetic Analysis of B-CLL Patients with Aggressive Disease

We tested a set of commercially available probes to determine the feasibility and accuracy of FISH in the detection of abnormalities in 13 patients with Chronic Lymphocytic Leukemia (CLL) with a particular aggressive clinical disease. We utilized three different probes for the 13q12-14 region, one for the centromeric region of chromosome 12, one for the P53 gene at 17p13.1 and one for 3′-5′ IGH at 14q32, covering the entire region of IGH, thus potentially allowing to detect more rearrangements. Conventional cytogenetic study showed a normal karyotype in 8/13 patients. FISH was able to detect chromosomal abnormalities in 10/13 pts (85%): +12 in 4 pts (38%); del 13q in 4 (38%); del 17p in 3 (35%); del of 5′-IGH in 1 (15%). In conclusion FISH confirmed its ability to improve the detection of cytogenetic abnormalities especially in patients with an aggressive disease.     

Molecular cytogenetic analysis of B-CLL patients with aggressive disease

We tested a set of commercially available probes to determine the feasibility and accuracy of FISH in the detection of abnormalities in 13 patients with Chronic Lymphocytic Leukemia (CLL) with a particular aggressive clinical disease. We utilized three different probes for the 13q12-14 region, one for the centromeric region of chromosome 12, one for the P53 gene at 17p13.1 and one for 3'-5' IGH at 14q32, covering the entire region of IGH, thus potentially allowing to detect more rearrangements. Conventional cytogenetic study showed a normal karyotype in 8/13 patients. FISH was able to detect chromosomal abnormalities in 10/13 pts (85%): +12 in 4 pts (38%); del 13q in 4 (38%); del 17p in 3 (35%); del of 5'-IGH in 1 (15%). In conclusion FISH confirmed its ability to improve the detection of cytogenetic abnormalities especially in patients with an aggressive disease.     

Relationship of patient survival and chromosome anomalies detected in metaphase and/or interphase cells at diagnosis of myeloma

The clinical efficacy of evaluating genetic anomalies in metaphase cells versus interphase nuclei for multiple myeloma (MM) is poorly understood. Therefore, survival for 154 patients with newly diagnosed untreated MM was compared with results from analysis of metaphase and interphase cells. Metaphases were studied by conventional cytogenetics and fluorescent-labeled DNA probes (fluorescence in situ hybridization [FISH]), whereas inter-phase nuclei were evaluated only by FISH. All FISH studies were done using DNA probes to detect t(4;14)(p16;q32), t(11;14)(q13;q32), t(14;16)(q32;q23), del(17) (p13.1), and chromosome 13 anomalies. Metaphases were abnormal by cytogenetics and/or metaphase FISH in 61 (40%) patients. Abnormal interphase nuclei were observed in 133 (86%) patients, including each patient with abnormal metaphases. FISH was a necessary adjunct to cytogenetics to detect t(4;14) and t(14;16) in metaphase cells. Patient survival was especially poor for patients with greater than 50% abnormal interphase nuclei, although this result was more likely due to level of plasma cells than specific chromosome anomalies. For metaphase data, patients with t(4;14), t(14;16), del(17) (p13.1), and/or chromosome 13 anomalies (primarily monosomy 13) had poor survival. A different outcome was observed for interphase data as patients with t(4;14) or t(14;16) had poor survival, whereas patients with chromosome 13 anomalies had intermediate survival: interphase FISH did not substitute for metaphase analysis.     

Translocations of 14q32 and deletions of 13q14 are common chromosomal abnormalities in systemic amyloidosis

Systemic monoclonal immunoglobulin light chain amyloidosis (AL) is associated with clonal plasma cell dyscrasias that are often subtle and non-proliferating. AL shares numerical chromosomal changes with multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS). Illegitimate translocations involving the immunoglobulin heavy chain gene (IGH) at 14q32 and deletions of the long arm of chromosome 13, [del(13q)], commonly occur in MM, MGUS and plasma cell leukaemia. In AL IGH rearrangements have been identified but, to date, there are no reports of del(13q). In this study of 32 patients with AL, 24 with systemic and eight with localized disease, translocations involving IGH and del(13q) were found using dual-colour interphase fluorescence in situ hybridization (FISH). IGH translocations were observed in 11 patients (37% overall and in 46% with systemic disease), of which nine had the IGH/CCND1 fusion from t(11;14)(q13;q32). Two showed IGH translocations other than the t(11;14) or t(4;14)(p16;q32). In one of these patients a breakpoint within the constant region of IGH between Calpha1 and Calpha2 was indicated. In the second a deletion covering Calpha1 and Calpha2 accompanied the translocation. Ten patients (27% overall and 33% of those with systemic disease) showed del(13q). The gain or loss of IGH and CCND1 signals provided evidence of numerical chromosomal changes in three patients.     

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.     

Biallelic deletion 13q14.3 in patients with chronic lymphocytic leukemia: cytogenetic, FISH and clinical studies

Background and objective:  Monoallelic deletion of 13q14.3 (13q14x1) is the most common abnormality in chronic lymphocytic leukemia (CLL). As a sole alteration, it predicts a favorable outcome. Biallelic 13q14.3 (13q14x2) deletion or concomitant 13q14x1/13q14x2 has been scarcely evaluated in the literature. We present the clinical, cytogenetic and fluorescence in situ hybridization (FISH) analysis of six CLL patients with normal karyotypes and 13q14x2 and their comparison to cases with 13q14x1 as a single abnormality.
Patients and methods:  A total of 103 CLL patients were studied. Cytogenetic and FISH analysis were performed on stimulated peripheral blood lymphocytes. Specific fluorescence DNA probes for CLL were used.
Results:  Six out of 103 (5.8%) patients showed normal karyotypes and 13q14x2. It was observed as a single alteration in one patient and combined with 13q14x1 in five cases. Biallelic clones were larger than monoallelic ones in 3/5 patients (60%). The comparison of clinical and hematological data between 13q14x1 and 13q14x2 groups showed progression of the disease in all 13q14x2 patients respect to 12/32 (37.5%) cases with 13q14x1 ( P  = 0.008), significant differences in the distribution by Rai stage ( P  = 0.042) and a tendency of a higher lactate dehydrogenase level in 13q14x2 patients ( P  = 0.054). Treatment free survival for 13q14x2 group was 28.5 months, shorter than those observed in patients with 13q14x1 alone (49 months).
Conclusions:  Our data would suggest that 13q14x2 could represent a more aggressive FISH anomaly than 13q14x1 alone, probably as a consequence of clonal evolution and/or due to the complete inactivation of this critical region by mean of more complex mechanisms.     

Molecular markers for diagnosis of Prader-Willi syndrome in thai patients by fish

Paternal microdeletion of chromosome 15 at q11-q13 has been reported in 75% of Prader-Willi syndrome (PWS) patients in western countries. Diagnosis of PWS in Thailand is mainly based on clinical observation and, in some cases, confirmed by conventional cytogenetic analysis. Loss of a tiny segment in this region (microdeletion) has made it difficult to discriminate from the normal karyotype. An attempt to solve this problem has been made by using a high resolution chromosome culture. However, this method is a tedious and time-consuming technique which is suitable for only experienced cytogeneticists. We report molecular cytogenetic analysis for PWS in Thai patients using FISH in addition to standard GTG- banding chromosome analysis. Nine Thai patients clinically diagnosed or with a suspicion of PWS were investigated. The FISH probes consist of the region-specific probes (SNRPN or D15S10 probe) and two chromosome 15-specific control probes (D15Z1 centromeric and PML chromosome 15 long arm probe). Bright field and FISH programs of an automatic karyotyper were applied to facilitate the efficiency of the chromosome analysis. We found that 2 out of 9 patients showed a deletion at 15q11-q13 region by standard GTG chromosome analysis while 4 out of 9 patients showed a delation in this region by FISH. Consistent losing of SNRPN and D15S10 signals in FISH was observed in these patients. This forty-four per cent deletion is considerably lower than those reported from western countries. We propose that DNA methylation at SNRPN promoter as well as structural abnormalities in other chromosome regions might also play a role in the etiology of this disorder in Thais, which should be investigated further.     

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。     

Neoplastic circulating endothelial cells in multiple myeloma with 13q14 deletion

In multiple myeloma (MM), circulating endothelial cells (CECs) represent a vascular marker of angiogenesis and may reflect tumor mass. In this report, we showed that, in 5 MM patients with 13q14 deletion, CECs carried the same chromosome aberration as the neoplastic plasma cells (11%-32% of CECs with 13q14 deletion). Most of the CECs displayed immunophenotypic features of endothelial progenitor cells as they expressed CD133, a marker gradually lost during endothelial differentiation and absent on mature endothelial cells. To the contrary, in 3 patients with monoclonal gammopathy of undetermined significance and 13q14 deletion, CECs were cytogenetically normal and had a mature immunophenotype. In MM CECs, immunoglobulin genes were clonally rearranged. These findings suggest a possible origin of CECs from a common hemangioblast precursor that can give rise to both plasma cells and endothelial cells and point to a direct contribution of MM-derived CECs to tumor vasculogenesis and possibly to the spreading and progression of the disease.     

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.     

Frequency and prognostic value of chromosome abnormalities in multiple myeloma

Chromosomal aberrations have been shown to significantly affect survival in multiple myeloma (MM), but few cytogenetic analyses among Japanese MM patients have been reported. Using a commercial laboratory, we performed interphase fluorescent in situ hybridization (FISH), as well as a conventional metaphase cytogenetic study (G-banding), among 106 of 131 patients between April 1997 and February 2007. Karyotype abnormalities were found in 21.2% (21 of 99 patients). Del(13q), del(17p), del(11q), t(11;14) and t(4;14) were detected by FISH in 36.0% (31/86), 24.7% (19/77), 7.6% (5/64), 18.2% (12/66) and 10.4% (7/67) of patients, respectively. The prevalence of abnormalities detected by G-banding was lower than that reported in European countries, but when compared with FISH studies, no difference was observed. Prognostic analyses of patients with these abnormal chromosomes revealed that those with abnormal karyotype and del(13q), t(4;14), as detected by FISH, had significantly poorer survival. This study suggests that the prevalence of chromosome abnormalities among Japanese patients is similar to that for European populations, and that chromosome studies by G-banding and FISH are essential to predict survival.