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.     

Chromosome aberrations in a series of 120 multiple myeloma cases with abnormal karyotypes

We identified 120 multiple myeloma (MM) cases with satisfactory cytogenetic evaluation and abnormal karyotypes. Hyperdiploid karyotype was found in 77 cases (64%), hypodiploid in 30 cases (25%), and the remaining 13 cases (11%) had a pseudodiploid karyotype. The most common numerical abnormalities were gains of chromosomes 15, 9, 3 followed by chromosomes 19, 11, 7, 21, and 5. Whole chromosome losses were also frequent involving primarily chromosomes X/Y, 8, 13, 14, and 22. Most cases showed also structural rearrangements leading to del(1p), dup(1q), del(5q), del(6q), del(8p), del(9p), del(13q), and del(17p). Chromosome 13/13q deletion was found in 52% of cases; complete loss of 13 was observed in 73% of cases, whereas 27% had interstitial deletions. In addition, 13/13q deletions occurred in 75% of nonhyperdiploid myeloma but only 39% of the hyperdiploid had 13/13q deletions. Translocations affecting 14q32/IGH region was seen 40 cases; t(11;14)(q13;q32) in 17 cases, t(14;16)(q32;q23) and t(8;14)(q24;q32) in three cases each, and t(6;14)(p21;q32) and t(1;14)(q21;q32) in two cases each. The remaining 14q32 translocations had various t(V;14) partners or of an undetermined origin. Remarkably, the 14q32/IGH translocations were less frequent in the hyperdiploid karyotypes than the nonhyperdiploid karyotypes (17 vs. 63%). Fourteen cases showed break at 8q24/CMYC site; seven of those had Burkitt's-type translocations. Our results revealed that conventional cytogenetics remains an important tool in elucidating the complex and divers genetic anomalies of MM. Cytogenetics identifies two distinct groups of MM, hyperdiploid and nonhyperdiploid, and establishes the presence of prognostic chromosomal markers such as 13/13q, 17p, 8q24, and 16q aberrations.     

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.     

Detection of t(4;14)(p16.3;q32) chromosomal translocation in multiple myeloma by double-color fluorescent in situ hybridization.

Chromosomal translocations involving the immunoglobulin heavy chain (IGH) locus at chromosome 14q32 represent a common mechanism of oncogene activation in lymphoid malignancies. In multiple myeloma (MM), variable chromosome partners have been identified by conventional cytogenetics, including the 11q13, 8q24, 18q21, and 6p21 loci. We and others have recently reported a novel, karyotypically undetectable chromosomal translocation t(4;14)(p16. 3;q32) in MM-derived cell lines, as well as in primary tumors. The 4p16.3 breakpoints are relatively scattered and located less than 100 kb centromeric of the fibroblast growth factor receptor 3 (FGFR3) gene or within the recently identified WHSC1 gene, both of which are apparently deregulated by the translocation. To assess the frequency of the t(4;14)(p16.3;q32) translocation in MM, we performed a double-color fluorescent in situ hybridization (FISH) analysis of interphase nuclei with differently labeled probes specific for the IGH locus (a pool of plasmid clones specific for the IGH constant regions) or 4p16.3 (yeast artificial chromosome (YAC) 764-H1 spanning the region involved in breakpoints). Thirty MM patients, the MM-derived cell lines KMS-11 and OPM2, and six normal controls were examined. The identification of a t(4;14) translocation, evaluated as the presence of a der(14) chromosome, was based on the colocalization of signals specific for the two probes; a cutoff value of 15% (mean + 3 standard deviation [SD]) derived from the interphase FISH of the normal controls (range, 5% to 11%; mean +/- SD, 8.16 +/- 2.2) was used for the quantification analysis. In interphase FISH, five patients (one in clinical stage I, two in stage II, one in stage III, and a plasma cell leukemia) were found to be positive (approximately 15%). FISH metaphases with split or colocalized signals were detected in only two of the translocated cases and confirmed the pattern found in the interphase nuclei. Furthermore, in three of the five cases with the translocation, FISH analysis with the IGH joining probe (JH) showed the presence of the reciprocal product of the translocation [der(4) chromosome]. Overall, our study indicates that the t(4;14)(p16. 3;q32) chromosomal translocation is a recurrent event in MM tumors and may contribute towards the detection of this lesion and our understanding of its pathogenetic and clinical implications in MM.     

Waldenström macroglobulinemia neoplastic cells lack immunoglobulin heavy chain locus translocations but have frequent 6q deletions

Lymphoplasmacytic lymphoma (LPL) is characterized by t(9;14)(p13;q32) in 50% of patients who lack paraproteinemia. Waldenstr?m macroglobulinemia (WM), which has an immunoglobulin M (IgM) paraproteinemia, is classified as an LPL. Rare reports have suggested that WM sometimes is associated with 14q23 translocations, deletions of 6q, and t(11;18)(q21;q21). We tested for these abnormalities in the clonal cells of WM patients. We selected patients with clinicopathologic diagnosis of WM (all had IgM levels greater than 1.5 g/dL). Southern blot assay was used to detect legitimate and illegitimate IgH switch rearrangements. In addition to conventional cytogenetic (CC) and multicolor metaphase fluorescence in situ hybridization (M-FISH) analyses, we used interphase FISH to screen for t(9;14)(p13;q32) and other IgH translocations, t(11;18)(q21;q21), and 6q21 deletions. Genomic stability was also assessed using chromosome enumeration probes for chromosomes 7, 9, 11, 12, 15, and 17 in 15 patients. There was no evidence of either legitimate or illegitimate IgH rearrangements by Southern blot assay (n = 12). CC (n = 37), M-FISH (n = 5), and interphase FISH (n = 42) failed to identify IgH or t(11;18) translocations. Although tumor cells from most patients were diploid for the chromosomes studied, deletions of 6q21 were observed in 42% of patients. In contrast to LPL tumors that are not associated with paraproteinemia and that have frequent t(9;14)(p13;q32) translocations, IgH translocations are not found in WM, a form of LPL tumor distinguished by IgM paraproteinemia. However, WM tumor cells, which appear to be diploid or near diploid, often have deletions of 6q21.     

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.     

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)     

Genomic abnormalities in monoclonal gammopathy of undetermined significance

Translocations involving immunoglobulin (Ig) loci and chromosome 13 monosomy (Delta 13) are frequent cytogenetic findings in multiple myeloma (MM). Similar chromosomal aberrations have been identified in the monoclonal gammopathy of undetermined significance (MGUS), but their prevalence and significance remain uncertain. Bone marrow from 72 patients with MGUS (n = 62) and smoldering MM (n = 10) was evaluated for translocations between the Ig heavy chain (IgH) and chromosomes 4, 11, and 16, translocations involving Ig light chain-lambda (IgL-lambda, and Delta 13. Fluorescence in situ hybridization (FISH) analysis was done on clonal plasma cells (PCs) detected by immunofluorescence (cIg-FISH) of the cytoplasmic light chain. We also studied cells for cyclin D1 and FGFR3 up-regulation by immunohistochemistry and immunofluorescence, respectively. Twenty-seven (46%) of 59 patients had IgH translocations, and 4 (11%) of 37 had an IgL-lambda translocation. A t(11;14)(q13;q32) was found in 15 (25%) of 59 patients, a t(4;14)(p16.3;q32) in 9% of patients, and a t(14;16)(q32;q23) in 5% of patients. All patients with t(4;14)(p16.3;q32) tested (n = 3) had intense cytoplasmic fluorescence with an anti-FGFR3 antibody. PC nuclear staining of cyclin D1 was only observed in patients with t(11;14)(q13;q32); Delta 13 was detected in the clonal PCs in 50% of patients. The percentage of abnormal PCs varied with any given abnormality. No obvious clinical or biologic correlations were associated with these chromosome abnormalities. Similar translocations are found in both MGUS and MM, including t(4;14)(p16.3;q32) and t(14;16)(q32;q23). Moreover, Delta 13 is common in MGUS and unlikely to play a predominant role in the evolution of MGUS to MM.     

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.     

New chromosome abnormalities and lack of BCL-6 gene rearrangements in Argentinean diffuse large B-cell lymphomas

OBJECTIVES: Diffuse large B-cell lymphoma (DLBCL) is the most common form of non-Hodgkin lymphomas. Cytogenetic studies have revealed a broad spectrum of clonal genetic abnormalities and complex karyotypes. The purpose of this study was to contribute to the understanding of the genomic alterations associated with this group of lymphomas. METHODS: Cytogenetic, fluorescence in situ hybridization (FISH) and molecular analyses were performed in 30 cases with DLBCL: 20 de novo DLBCL (dn-DLBCL) and 10 DLBCL secondary to follicular lymphoma (S-DLBCL). RESULTS: A total of 37 different structural chromosomal rearrangements were found: 27% translocations, 54% deletions, and 19% other alterations. Chromosomes 8, 6, 2, and 9 were the most commonly affected. Interestingly, translocation t(3;14)(q27;q32) and/or BCL-6 gene rearrangements were not observed either by cytogenetic studies or by FISH analysis. Fifteen novel cytogenetic alterations were detected, among them translocations t(2;21)(p11;q22) and t(8;18)(q24;p11.3) appeared as sole structural abnormalities. Translocation t(14;18)(q32;q21) and/or BCL-2-IGH gene rearrangements were the genomic alterations most frequently observed: 50% of S-DLBCL and 30% of dn-DLBCL. Deletions del(4)(q21), del(6)(q27), del(8)(q11), and del(9)(q11) were recurrent. The most common gains involved chromosome regions at 12q13-q24, 7q10-q32, and 17q22-qter; 6q was the most frequently deleted region, followed by losses at 2q35-qter, 7q32-qter, and 9q13-qter. Four novel regions of loss were identified: 5q13-q21, 2q35-qter (both recurrent in our series), 4p11-p12, and 17q11-q12. CONCLUSIONS: These studies emphasize the value of combining conventional cytogenetics with FISH and molecular studies to allow a more accurate definition of the genomic aberrations involved in DLBCL.     

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.     

A Retrospective Analysis of Cytogenetic and Clinical Characteristics in Patients With Multiple Myeloma

BackgroundCytogenetic alterations in patients with multiple myeloma (MM) represent important risk factors in terms of prognosis. In this study, the impact of the cytogenetic aberrations of MM on patient clinical features and outcome was investigated.MethodsConventional cytogenetic analysis with R-banding technique and molecular cytogenetic characterization by interphase fluorescence in situ hybridization (FISH) were used to detect aberrant chromosomal arrangements, including 17p13 and 13q14 deletions, 14q32 rearrangement and 1q21 amplification, in bone marrow nucleated cells from 65 patients.ResultsAbout 16.9% of patients showed aberrations by conventional cytogenetic analysis, whereas 49.2% of patients showed aberrations by interphase FISH analysis. Abnormalities of 13q14, 1q21, 14q32 and 17p13 were detected in 27.7%, 13.8%, 16.9% and 29.2%, respectively. Patients with a 13q14 deletion or combined with 17p13 deletion frequently had a late stage of the disease, and tended to have elevated serum levels of β₂ microglobulin and lower levels of albumin. The progression-free survival and overall survival of FISH-positive patients were lower than for those without detectable abnormalities, especially in the conventional chemotherapy arm.ConclusionsThese findings demonstrate that myeloma cells are prone to exhibiting a complex aberration and that FISH is superior to conventional cytogenetic analysis with a higher detection rate of chromosomal abnormalities. Patients with a 17p13 or 13q14 deletion, 14q32 rearrangement and 1q21 amplification were more likely to have a poor prognosis for MM.     

Prognostic and biologic significance of chromosomal imbalances assessed by comparative genomic hybridization in multiple myeloma

Cytogenetic abnormalities, evaluated either by karyotype or by fluorescence in situ hybridization (FISH), are considered the most important prognostic factor in multiple myeloma (MM). However, there is no information about the prognostic impact of genomic changes detected by comparative genomic hybridization (CGH). We have analyzed the frequency and prognostic impact of genetic changes as detected by CGH and evaluated the relationship between these chromosomal imbalances and IGH translocation, analyzed by FISH, in 74 patients with newly diagnosed MM. Genomic changes were identified in 51 (69%) of the 74 MM patients. The most recurrent abnormalities among the cases with genomic changes were gains on chromosome regions 1q (45%), 5q (24%), 9q (24%), 11q (22%), 15q (22%), 3q (16%), and 7q (14%), while losses mainly involved chromosomes 13 (39%), 16q (18%), 6q (10%), and 8p (10%). Remarkably, the 6 patients with gains on 11q had IGH translocations. Multivariate analysis selected chromosomal losses, 11q gains, age, and type of treatment (conventional chemotherapy vs autologous transplantation) as independent parameters for predicting survival. Genomic losses retained the prognostic value irrespective of treatment approach. According to these results, losses of chromosomal material evaluated by CGH represent a powerful prognostic factor in MM patients.     

Close relation between 14q32/IGH translocations and chromosome 13 abnormalities in multiple myeloma: a high incidence of 11q13/CCND1 and 16q23/MAF

Many B-cell tumors have chromosomal translocations that result from failures of the immunoglobulin (Ig) gene during V(D)J recombination, somatic hypermutation (SHM), and class switch recombination (CSR). Nearly half of all multiple myeloma (MM) patients have 14q32/IGH translocations in CSR, including the five common translocations of 11q13/CCND1, 6p21/CCND3, 4p16/FGFR3, 16q23/MAF, and 20q11/MAFB. Although 14q32/IGH translocations are closely related to the biological features of MM, the most consistent and powerful prognostic factor has been reported to be the loss of all (monosomy 13/−13) or part of chromosome 13 (del(13)(q14)/13q−). Our fluorescence in situ hybridization (FISH) analysis method was designed to detect −13/13q− and 14q32/IGH rearrangements in 23 MM patients. FISH disclosed 14q32/IGH translocations in 10 of the 23 (43.5%) patients. The common translocation partners of 14q32/IGH were 11q13/CCND1 (five patients) and 16q23/MAF (four patients), followed in third place by 4p16/FGFR3 (one patient). Nine of the ten patients carrying 14q32/IGH translocations had −13/13q−. Abnormalities of chromosome 13 included −13 in seven (70%) and del(13)(q14) in two (20%). Our results suggest a significant correlation between the presence of 14q32/IGH translocations and chromosome 13 abnormalities (P = 0.0276) in MM patients.     

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.     

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.     

Cytogenetic studies in splenic lymphoma with villous lymphocytes

Summary. We report the cytogenetic findings on 31 cases of splenic lymphoma with villous lymphocytes (SLVL). TPA stimulated cells from peripheral blood (28 cases), spleen (two cases) and lymph node (one case) with SLVL have been analysed. A clonal chromosome abnormality was found in 27/31 patients (87%): this was identified as a simple abnormality in 12 cases and a complex one in 15. Four recurring abnormalities were seen: t(11:14) (q13:q32)in five patients, deletions or translocations involving 7q in seven patients. iso 17q in four patients and translocations involving 2p11 in four patients. The high frequency of clonal chromosome abnormalities in SLVL contrasts with the usually benign clinical course of this disease.
Abnormalities found frequently in patients with chronic lymphocytic leukaemia (CLL) such as trisosmy 12 and deletions or translocations involving 13q14 were each seen in only one patient. No case had the t(14:18) characteristic of follicular lymphoma.
Our findings demonstrate the high frequency of clonal and often complex chromosome abnormalities in SLVL. Although a unique chromosome rearrangement has not been identified, a pattern of four recurrent abnormalities has emerged. Our results suggest that SLVL is distinct on cytogenetic grounds from B-CLL and follicular lymphoma but shows similarity with mantle cell lymphoma, lymphoplasmacytic lymphoma and B-PLL.     

Clinical and biologic implications of recurrent genomic aberrations in myeloma

Nonrandom recurrent chromosomal abnormalities are ubiquitous in multiple myeloma (MM) and include, among others, translocations of the immunoglobulin heavy chain locus (IgH). IgH translocations in MM result in the up-regulation of oncogenes, and include more commonly t(11;14)(q13;q32), t(4;14)(p16;q32), and t(14;16)(q32;q23). Based on the recurrent nature of these translocations and their finding since the early stages of the plasma cell (PC) disorders, we hypothesized that they would confer biologic and clinical variability. In addition, deletions of 13q14 and 17p13 have also been associated with a shortened survival. We used cytoplasmic Ig-enhanced interphase fluorescent in situ hybridization to detect deletions (13q14 and 17p13.1), and translocations involving IgH in 351 patients treated with conventional chemotherapy entered into the Eastern Cooperative Oncology Group clinical trial E9486/9487. Translocations were frequently unbalanced with loss of one of the derivative chromosomes. The presence of t(4; 14)(p16;q32) (n = 42; 26 vs 45 months, P <.001), t(14;16)(q32;q23) (n = 15; 16 vs 41 months, P =.003), - 17p13 (n = 37; 23 vs 44 months, P =.005), and - 13q14 (n = 176; 35 vs 51 months, P =.028) were associated with shorter survival. A stratification of patients into 3 distinct categories allowed for prognostication: poor prognosis group (t(4;14)(p16;q32), t(14; 16)(q32;q23), and - 17p13), intermediate prognosis (- 13q14), and good prognosis group (all others), with median survivals of 24.7, 42.3, and 50.5 months, respectively (P <.001). This molecular cytogenetic classification identifies patients into poor, intermediate, and good risk categories. More importantly it provides further compelling evidence that MM is composed of subgroups of patients categorized according to their underlying genomic aberrations.     

Absence of clonal chromosomal relationship between concomitant B-CLL and multiple myeloma--a report on two cases

B-cell chronic lymphocytic leukemia (B-CLL) and multiple myeloma (MM) are chronic B-cell malignancies that represent different stages of B-cell maturation. Occasionally, both diseases are present in the same patient, and this raises the question of clonal associations between the two neoplasms. We here report on two patients with concomitant B-CLL and MM. Clonal chromosomal abnormalities in both lymphocytic cells and plasma cells were studied by interphase fluorescence in situ hybridization (FISH) using a panel of 24 chromosome- and region-specific DNA probes. In the first patient, cytogenetics revealed 47, X, t(Y;22)(p11;q10), +12, dell4(q21q32). By FISH, +12 was present in lymphoid cells, but not in plasma cells. MM cells were characterized by multiple chromosomal gains (1, 11q23) and losses (5q, 10, 13q14, 15, 17p13, Y), which were all undetectable in lymphoid cells. The second patient, in whom no clonal abnormalities were obtained by conventional cytogenetic analysis, had lymphoid cells with loss of 8q24 by FISH. In contrast, evidence for a gain of 8q24 (consistent with amplification of c-myc) was obtained in 13% of plasma cells. Plasma cells were further characterized by gains of chromosomes 1, 3, 11, 18, and Y. We thus conclude that this comprehensive molecular cytogenetic analysis demonstrates the existence of two clonally distinct B-cell malignancies in both patients.