Translocation T(4;14)(p16.3;q32) is a recurrent genetic lesion in primary amyloidosis

A Strategy for the Selection of RT-qPCR Reference Genes Based on Publicly Available Transcriptomic Datasets

In the next-generation sequencing era, RT-qPCR is still widely employed to quantify levels of nucleic acids of interest due to its popularity, versatility, and limited costs. The measurement of transcriptional levels through RT-qPCR critically depends on reference genes used for normalization. Here, we devised a strategy to select appropriate reference genes for a specific clinical/experimental setting based on publicly available transcriptomic datasets and a pipeline for RT-qPCR assay design and validation. As a proof-of-principle, we applied this strategy to identify and validate reference genes for transcriptional studies of bone-marrow plasma cells from patients with AL amyloidosis. We performed a systematic review of published literature to compile a list of 163 candidate reference genes for RT-qPCR experiments employing human samples. Next, we interrogated the Gene Expression Omnibus to assess expression levels of these genes in published transcriptomic studies on bone-marrow plasma cells from patients with different plasma cell dyscrasias and identified the most stably expressed genes as candidate normalizing genes. Experimental validation on bone-marrow plasma cells showed the superiority of candidate reference genes identified through this strategy over commonly employed “housekeeping” genes. The strategy presented here may apply to other clinical and experimental settings for which publicly available transcriptomic datasets are available.

Genetic pathogenesis of immunoglobulin light chain amyloidosis: basic characteristics and clinical applications

Immunoglobulin light chain amyloidosis (AL) is an indolent plasma cell disorder characterized by free immunoglobulin light chain (FLC) misfolding and amyloid fibril deposition. The cytogenetic pattern of AL shows profound similarity with that of other plasma cell disorders but harbors distinct features. AL can be classified into two primary subtypes: non-hyperdiploidy and hyperdiploidy. Non-hyperdiploidy usually involves immunoglobulin heavy chain translocations, and t(11;14) is the hallmark of this disease. T(11;14) is associated with low plasma cell count but high FLC level and displays distinct response outcomes to different treatment modalities. Hyperdiploidy is associated with plasmacytosis and subclone formation, and it generally confers a neutral or inferior prognostic outcome. Other chromosome abnormalities and driver gene mutations are considered as secondary cytogenetic aberrations that occur during disease evolution. These genetic aberrations contribute to the proliferation of plasma cells, which secrete excess FLC for amyloid deposition. Other genetic factors, such as specific usage of immunoglobulin light chain germline genes and light chain somatic mutations, also play an essential role in amyloid fibril deposition in AL. This paper will propose a framework of AL classification based on genetic aberrations and discuss the amyloid formation of AL from a genetic aspect.

Emerging Therapeutics for the Treatment of Light Chain and Transthyretin Amyloidosis

Cardiac amyloidosis is a restrictive cardiomyopathy that results from the deposition of misfolded light chain or transthyretin proteins, most commonly, in cardiac tissue. Traditionally, treatment options for light chain (AL) and transthyretin (ATTR) amyloidosis have been limited. However, there are now multiple novel therapeutics in development and several therapeutics recently approved that promise to revolutionize clinical management of AL and ATTR. Most of these agents disrupt specific stages of amyloidogenesis such as light chain or transthyretin protein production, formation of amyloidogenic intermediates, or amyloid fibril aggregation. Others aim to remove existing amyloid tissue deposits using monoclonal antibody technology. Although these advances represent an important step forward in the care of cardiac amyloidosis patients, additional studies are needed to define the optimal treatment paradigms for AL and ATTR and to validate clinical, imaging, or serum biomarker strategies that may confirm a cardiac response to therapy.

Discovery platform for inhibitors of IgH gene enhancer activity

Immunoglobulin heavy chain (IgH) translocations are common and early oncogenic events in B cell and plasma cell malignancies including B cell non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM). IgH translocations bring oncogenes into close proximity with potent enhancer elements within the IgH locus, leading to oncogene up-regulation. As IgH enhancer activity is tightly controlled by B cell lineage-specific signaling and transcriptional networks, we hypothesized that IgH enhancers are potentially druggable targets/elements. To test this, we developed a molecular imaging-based high-throughput screening platform for discovering inhibitors of IgH enhancer-driven transcriptional activity. As proof of concept, we identified a low micromolar potency molecule (compound 30666) that inhibited immunoglobulin production by MM cells and blocked expression of an array of IgH translocation-induced oncogenes (CCND1, FGFR3/MMSET, and MYC) in MM and NHL cell lines. Prolonged exposure to 30666 significantly reduced the viability of IgH translocation-positive NHL and MM cells, but was less effective against cells lacking IgH translocations. Compound 30666 exhibited suitable pharmacological properties, including metabolic stability in liver microsomes and oral bioavailability in mice, and demonstrated preclinical anti-MM activity in a plasmacytoma mouse model. Our work suggests that IgH enhancers are attractive and potentially druggable targets for IgH translocation driven malignancies.

Burden of cytogenetically abnormal plasma cells in light chain amyloidosis and their prognostic relevance

We performed cytoplasmic fluorescence in situ hybridization assays of light chain amyloidosis (AL). In total, 234 patients were enrolled: 28 patients with AL, 24 with monoclonal gammopathy of undetermined significance (MGUS), and 182 with multiple myeloma (MM). Chromosomal abnormalities were detected in 13 of 22 (59%) AL patients without MM. All 13 patients demonstrated IGH rearrangement, and t(11;14)/IGH-CCND1 was most frequent (32%). Chromosome gain was not observed in AL patients without MM. These findings were dissimilar to findings in MGUS patients, in whom trisomy 9 was the most frequent abnormality. Of 6 AL patients with MM, 5 (83%) patients had cytogenetic abnormalities: 1q gain (4/6, 67%), gains of chromosome 9 (3/6, 50%), IGH rearrangement and RB1 (13q) deletions (2/6 each, 33%). The percentage of clonal plasma cells among total plasma cells was variable (median, 75%; range, 16-100%) for AL patients without MM, which was lower than the results for MM patients (median 100%). The overall survival of AL patients without MM was not significantly different according to the presence of cytogenetic abnormalities (P=0.510). In summary, among Korean AL patients, IGH rearrangement was the most frequent cytogenetic abnormality and cytogenetic aberration patterns differ compared with MGUS and MM patients.

Immunoglobulin Light Chain Systemic Amyloidosis

Immunoglobulin light chain amyloidosis (AL) is a rare, complex disease caused by misfolded free light chains produced by a usually small, indolent plasma cell clone. Effective treatments exist that can alter the natural history, provided that they are started before irreversible organ damage has occurred. The cornerstones of the management of AL amyloidosis are early diagnosis, accurate typing, appropriate risk-adapted therapy, tight follow-up, and effective supportive treatment. The suppression of the amyloidogenic light chains using the cardiac biomarkers as guide to choose chemotherapy is still the mainstay of therapy. There are exciting possibilities ahead, including the study of oral proteasome inhibitors, antibodies directed at plasma cell clone, and finally antibodies attacking the amyloid deposits are entering the clinic, offering unprecedented opportunities for radically improving the care of this disease.

Abnormal FISH in patients with immunoglobulin light chain amyloidosis is a risk factor for cardiac involvement and for death

Importance of interphase fluorescent in situ hybridization (FISH) with cytoplasmic staining of immunoglobulin FISH (cIg-FISH) on bone marrow is not well understood in light chain amyloidosis (AL). This is in contrast with multiple myeloma where prognostic and treatment related decisions are dependent on cytogenetic testing. This retrospective study reviewed 401 AL patients with cIg-FISH testing performed at our institution between 2004 and 2012. Eighty-one percent of patients had an abnormal cIg-FISH. Common abnormalities involved translocations of chromosome 14q32 (52%), specifically: t(11;14) (43%), t(14;16) (3%) and t(4;14) (2%). Other common abnormalities include monosomy 13/deletion 13q (30%), trisomies 9 (20%), 15 (14%), 11 (10%) and 3 (10%). Median overall survival for this cohort of patients is 3.5 years. When plasma cell burden was greater than 10% trisomies predicted for worse survival (44 vs 19 months), and when it was ⩽10% t(11;14) predicted for worse survival (53 months vs not reached). Abnormal cIg-FISH was significantly associated with advanced cardiac involvement, and remained a prognostic factor on multivariate analysis. This large AL cohort demonstrates that abnormal FISH at diagnosis is prognostic for survival and advanced cardiac disease. Particularly, trisomies and t(11;14) affect survival when degree of plasma cell burden is considered.

Al amyloidosis

Definition of the disease

AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils.

Epidemiology

AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50.

Clinical description

The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis.

Diagnostic methods

The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the systemic nature of the disease, non-invasive biopsies such as abdominal fat aspiration should be considered before taking biopsies from involved organs, in order to reduce the risk of bleeding complications.

Differential diagnosis

Systemic AL amyloidosis should be distinguished from other diseases related to deposition of monoclonal LC, and from other forms of systemic amyloidosis. When pathological studies have failed to identify the nature of amyloid deposits, genetic studies should be performed to diagnose hereditary amyloidosis.

Management

Treatment of AL amyloidosis is based on chemotherapy, aimed at controlling the underlying plasma clone that produces amyloidogenic LC. The hematological response should be carefully checked by serial measurements of serum free LC. The association of an alkylating agent with high-dose dexamethasone has proven to be effective in two thirds of patients and is considered as the current reference treatment. New agents used in the treatment of multiple myeloma are under investigation and appear to increase hematological response rates. Symptomatic measures and supportive care is necessary in patients with organ failure. Noticeably, usual treatments for cardiac failure (i.e. calcium inhibitors, β-blockers, angiotensin converting enzyme inhibitors) are inefficient or even dangerous in patients with amyloid heart disease, that should be managed using diuretics. Amiodarone and pace maker implantation should be considered in patients with rhythm or conduction abnormalities. In selected cases, heart and kidney transplantation may be associated with prolonged patient and graft survival.

Prognosis

Survival in AL amyloidosis depends on the spectrum of organ involvement (amyloid heart disease being the main prognosis factor), the severity of individual organs involved and haematological response to treatment.

The challenge of systemic immunoglobulin light-chain amyloidosis (Al)

The cardiac involvement and associated mortality that occur in systemic AL amyloidosis remain among the most challenging aspects of the systemic amyloid-related diseases. Monoclonal immunoglobulin light chains produced by a clone of plasma cells are usually the cause of symptoms and organ dysfunction via both poorly understood toxic effects of misfolded species and accumulation of interstitial amyloid fibrils in key viscera. Treatment is aimed at eliminating the clonal cells in order to eliminate toxic light chain production. Recent advances in therapy have helped many patients with AL achieve complete hematologic responses and significant reversal of organ damage but these benefits do not extend to that 10-15 % who present with advanced cardiac involvement. Even with cardiac transplant followed by effective therapy such as stem cell transplant, outcomes for these patients remain promising at best.

Hyperdiploidy is less frequent in AL amyloidosis compared with monoclonal gammopathy of undetermined significance and inversely associated with translocation t(11;14)

In multiple myeloma (MM) pathogenesis, hyperdiploidy and nonhyperdiploidy are recognized as 2 major cytogenetic pathways. Here, we assessed the role of hyperdiploidy in 426 patients with monoclonal plasma cell disorders, among them 246 patients with AL amyloidosis (AL), by interphase fluorescence in situ hybridization. Hyperdiploidy was defined by a well-established score requiring trisomies for at least 2 of the 3 chromosomes 5, 9, and 15. The hyperdiploidy frequency in AL was a mere 11% compared with 30% in monoclonal gammopathy of undetermined significance (P < .001) and 46% in AL with concomitant MM I (P < .001). Overall, hyperdiploidy was associated with an intact immunoglobulin, κ light chain restriction, higher age, and bone marrow plasmacytosis, but was unrelated to the organ involvement pattern in AL. Clustering of 6 major cytogenetic aberrations in AL by an oncogenetic tree model showed that hyperdiploidy and t(11;14) were almost mutually exclusive, whereas gain of 1q21 favored hyperdiploidy. Deletion 13q14 and secondary IgH translocations were equally distributed between ploidy groups. We conclude that the interphase fluorescence in situ hybridization–based hyperdiploidy score is also a feasible tool to delineate hyperdiploid patients in early-stage monoclonal gammopathies and that the cytogenetic pathogenetic concepts developed in MM are transferable to AL.

Translocation t(11;14) and survival of patients with light chain (AL) amyloidosis

BACKGROUND

Light chain amyloidosis is a rare plasma cell dyscrasia. Interphase fluorescence in situ hybridization (FISH) coupled to cytoplasmic staining of specific Ig (cIg-FISH) on bone marrow plasma cells has become well established in the initial evaluation of multiple myeloma, a related disorder. Little, however, is known about cytogenetic abnormalities in patients with light chain amyloidosis.

DESIGN AND METHODS

We reviewed 56 patients with light chain amyloidosis who had cIg-FISH performed as part of their routine clinical testing using the standard screening panel employed in multiple myeloma at our institution.

RESULTS

Seventy percent of patients had abnormal cIg-FISH, with the most common abnormalities being IgH translocations [48%]--including t(11;14) [39%], and t(14;16) [2%]--and del13/del13q [30%]. No t(4;14) or deletions of 17p (p53) were observed. Patients with t(11;14) had the lowest levels of clonal plasma cells, and those with del13 had the highest. The risk of death for patients harboring the t(11;14) translocation was 2.1 (CI 1.04-6.4), which on multivariate analysis was independent of therapy.

CONCLUSIONS

Although preliminary, our data would suggest that cIg-FISH testing is important in patients with light chain amyloidosis and that t(11;14) is an adverse prognostic factor in these patients.

Evaluation of the cytogenetic aberration pattern in amyloid light chain amyloidosis as compared with monoclonal gammopathy of undetermined significance reveals common pathways of karyotypic instability

Chromosomal aberrations (CAs) have emerged as important pathogenetic and prognostic factors in plasma cell disorders. Using interphase fluorescence in situ hybridization (FISH) analysis, we evaluated CAs in a series of 75 patients with amyloid light chain amyloidosis (AL) as compared with 127 patients with monoclonal gammopathy of unknown significance (MGUS). We investigated IgH translocations t(11;14), t(4;14), and t(14;16) as well as gains of 1q21, 11q23, and 19q13 and deletions of 8p21, 13q14, and 17p13, detecting at least one CA in 89% of the patients. Translocation t(11;14) was the most frequent aberration in AL, with 47% versus 26% in MGUS (P = .03), and was strongly associated with the lack of an intact immunoglobulin (P < .001), thus contributing to the frequent light chain subtype in AL. Other frequent aberrations in AL included deletion of 13q14 and gain of 1q21, which were shared by MGUS at comparable frequencies. The progression to multiple myeloma (MM) stage I was paralleled by an increased frequency of gain of 1q21 (P = .001) in both groups. Similar branching patterns were observed in an oncogenetic tree model, indicating a common mechanism of underlying karyotypic instability in these plasma cell disorders.

Genetics and molecular profiling of multiple myeloma: novel tools for clinical management?

The understanding of molecular events involved in multiple myeloma (MM) development as well as of mechanisms underlying sensitivity/resistance to anticancer drugs has been dramatically increased by the wide-spread use of modern technologies for genetic analysis, global gene expression and proteomic profiling. Such analytical approaches, which are presently supported by reliable bioinformatic tools, have depicted a new scenario for the development of molecular-based anti-MM agents and for predicting clinical outcome. IgH translocations or a hyperdiploid state are emerging as early genetic signatures of MM which lead to deregulated expression of cyclin D. At present however, the major challenge remains the definition of the potential role of cytogenetic techniques and molecular profiling technologies in individual patient management. Here we will describe the prospective potential and current achievements of such technologies which might produce major advancements in the treatment of this still incurable disease.

Multiple myeloma-associated AL amyloidosis: is a distinctive therapeutic approach warranted?

The natural history of multiple myeloma (MM) was revolutionized by the introduction of haematopoietic stem cell transplantation to the treatment armamentarium of this disease. Defined subgroups of MM patients (such as the elderly or dialysis-dependent) have required an individualized approach in order to minimize the transplant-related mortality. Little, however, is known about the management of 12-30% of MM patients with coexistent AL amyloidosis as the amyloidopathy is often overlooked and when recognized these patients commonly are excluded from clinical trials. While occult amyloidosis appears to have no impact on the toxicity and outcome of MM patients, the presence of symptomatic amyloidopathy clearly worsens their prognosis. Use of induction chemotherapy drugs that can cause further damage to the heart (Adriamycin), nervous system (Vincristine) or kidneys should be avoided as should lengthy delays in proceeding to autograft. Further, refining the transplant eligibility criteria for this subgroup of patients with co-existent amyloidopathy to include the number of organs involved and the degree of cardiac involvement (NYHA class, Troponins and NT-pro-BNP levels) along with melphalan dose-adjustment will minimize the treatment-related toxicity and mortality and possibly allow a reversal of the organ damage induced by the amyloidogenic light chain.

Clinical aspects of systemic amyloid diseases

Amyloidosis is a protein misfolding disorder in which soluble proteins aggregate as insoluble amyloid fibrils. Protein aggregates and amyloid fibrils cause functional and structural organ damage respectively. To date, at least 24 different proteins have been recognized as causative agents of amyloid diseases, localized or systemic. The two most common forms of systemic amyloidosis are light-chain (AL) amyloidosis and reactive AA amyloidosis due to chronic inflammatory diseases. beta(2)-microglobulin amyloidosis is a common complication associated with long-term hemodialysis. Hereditary systemic amyloidoses are a group of autosomal dominant disorders caused by mutations in the genes of several plasma proteins. Heterogeneity in clinical presentation, pattern of amyloid-related organ toxicity and rate of disease progression is observed among systemic amyloidoses. In particular, beta(2)-microglobulin presents unique clinical features compared to the other systemic forms. The phenotypic features of hereditary systemic amyloidoses may instead overlap those of the two more common forms of acquired amyloidoses mentioned above and therefore a correct diagnosis can not rely only on clinical grounds. Unequivocal identification of the deposited protein is essential in order to avoid misdiagnosis and inappropriate treatment. Amyloid deposits can be reabsorbed and organ dysfunction reversed if the concentration of the amyloidogenic protein is reduced or zeroed. At present, the most effective approach to treatment of the systemic amyloidoses involves shutting down, or substantially reducing the synthesis of the amyloid precursor, or, as in the case of beta(2)-microglobulin, promoting its clearance.

Genetics and cytogenetics of multiple myeloma: a workshop report

Much has been learned regarding the biology and clinical implications of genetic abnormalities in multiple myeloma. Because of recent advances in the field, an International Workshop was held in Paris in february of 2003. This summary describes the consensus recommendations arising from that meeting with special emphasis on novel genetic observations. For instance, it is increasingly clear that translocations involving the immunoglobin heavy-chain locus are important for the pathogenesis of one-half of patients. As a corollary, it also clear that the remaining patients, lacking IgH translocations, have hyperdiploidy as the hallmark of their disease. Several important genetic markers are associated with a shortened survival such as chromosome 13 monosomy, hypodiploidy, and others. The events leading the transformation of the monoclonal gammopathy of undetermined significance (MGUS) to myeloma are still unclear. One of the few differential genetic lesions between myeloma and MGUS is the presence of ras mutations in the latter. Gene expression platforms are capable of detecting many of the genetic aberrations found in the clonal cells of myeloma. Areas in need of further study were identified. The study of the genetic aberrations will likely form the platform for targeted therapy for the disease.

In multiple myeloma, t(4;14)(p16;q32) is an adverse prognostic factor irrespective of FGFR3 expression

This study analyzed the frequency and clinical significance of t(4;14)(p16;q32) in multiple myeloma (MM) among 208 patients with MM and 52 patients with monoclonal gammopathy of undetermined significance (MGUS); diagnosed between 1994 and 2001. Patients with the translocation were identified using reverse transcription-polymerase chain reaction (RT-PCR) to detect hybrid immunoglobulin heavy chain (IgH)-MMSET transcripts from the der(4) chromosome. We found 31 (14.9%) t(4;14)(+) MM patients and 1 (1.9%) t(4;14)(+) MGUS patient. IgH-MMSET hybrid transcripts were detected in bone marrow (BM) and blood. Breakpoint analysis revealed that 67.7% of t(4;14)(+) patients expressed hybrid transcripts potentially encoding full-length MMSET, whereas the remainder lacked one or more amino terminal exons. Expression of fibroblast growth factor receptor 3 (FGFR3), presumptively dysregulated on der(14), was detected by RT-PCR in only 23 of 31 (74%) patients with t(4;14)(+) MM. Patients lacking FGFR3 expression also lacked detectable der(14) products. Longitudinal analysis of 53 MM patients with multiple BM and blood samples showed that, over time, BM from t(4;14)(+) patients remained positive and that t(4;14)(-) patients did not acquire the translocation. IgH-MMSET hybrid transcripts and FGFR3 transcripts disappeared from blood during response to therapy. No correlation was observed between the occurrence of t(4;14) and known prognostic indicators. However, we find the t(4;14) translocation predicts for poor survival (P =.006; median, 644 days vs 1288 days; hazard ratio [HR], 2.0), even in FGFR3 nonexpressors (P =.003). The presence of t(4;14) is also predictive of poor response to first-line chemotherapy (P =.05). These results indicate a significant clinical impact of the t(4;14) translocation in MM that is independent of FGFR3 expression.

The enigma of ectopic expression of FGFR3 in multiple myeloma: a critical initiating event or just a target for mutational activation during tumor progression

The t(4;14)(p16.3;q32) translocation that occurs uniquely in a subset of multiple myeloma tumors results in ectopic expression of wild-type FGFR3 and enhanced expression of MMSET, a gene that is homologous to the MLL gene that is involved in acute myeloid leukemias. Wild-type FGFR3 appears to be weakly transforming in a hematopoietic murine model, whereas FGFR3 that contains kinase-activating mutations is strongly transforming in NIH3T3 cells and the hematopoietic model. The subsequent acquisition of FGFR3 kinase-activating mutations in some tumors with t(4;14) translocations confirms a role for FGFR3 in tumor progression. However, it remains to be proven if and how dysregulation of FGFR3 or MMSET mediates an early oncogenic process in multiple myeloma.

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.