Frequent upregulation of MYC in plasma cell leukemia

Cytogenetics in the management of multiple Myeloma: The guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Multiple myeloma (MM) is characterized by the accumulation of malignant plasma cells (PCs) in the bone marrow. Despite considerable advances in the treatment, MM is considered an incurable chronic disease with a very heterogeneous prognosis, mostly depending on genomic alterations whose complexity evolves over time. The cytogenetic analysis of MM is performed on CD138+ sorted PCs, in order to detect the following high risk cytogenetic abnormalities: t(4;14), 17p/TP53 deletion, 1q21 gain/amplification, 1p32 deletion, as well as t(11;14) because of its therapeutic implication. This minimal panel can be enlarged to detect other recurrent abnormalities, according to the prognostic score chosen by the laboratory. Although the knowledge of the genetic landscape of MM is evolving rapidly with improved molecular technologies, risk scores remain to be refined as they require more time for consensual validation. The GFCH present here the overview of genomics alterations identified in MM and related PCs diseases associated with their prognostic factor, when available, and recommendations from an expert group for identification and characterization of those alterations. This work is the update of previous 2016 recommendations.

Serum NMR-Based Metabolomics Profiling Identifies Lipoprotein Subfraction Variables and Amino Acid Reshuffling in Myeloma Development and Progression

Multiple myeloma (MM) is an incurable hematological cancer. It is preceded by monoclonal gammopathy of uncertain significance (MGUS)-an asymptomatic phase. It has been demonstrated that early detection increases the 5-year survival rate. However, blood-based biomarkers that enable early disease detection are lacking. Metabolomic and lipoprotein subfraction variable profiling is gaining traction to expand our understanding of disease states and, more specifically, for identifying diagnostic markers in patients with hematological cancers. This study aims to enhance our understanding of multiple myeloma (MM) and identify candidate metabolites, allowing for a more effective preventative treatment. Serum was collected from 25 healthy controls, 20 patients with MGUS, and 30 patients with MM. 1H-NMR (Nuclear Magnetic Resonance) spectroscopy was utilized to evaluate serum samples. The metabolite concentrations were examined using multivariate, univariate, and pathway analysis. Metabolic profiles of the MGUS patients revealed lower levels of alanine, lysine, leucine but higher levels of formic acid when compared to controls. However, metabolic profiling of MM patients, compared to controls, exhibited decreased levels of total Apolipoprotein-A1, HDL-4 Apolipoprotein-A1, HDL-4 Apolipoprotein-A2, HDL Free Cholesterol, HDL-3 Cholesterol and HDL-4 Cholesterol. Lastly, metabolic comparison between MGUS to MM patients primarily indicated alterations in lipoproteins levels: Total Cholesterol, HDL Cholesterol, HDL Free Cholesterol, Total Apolipoprotein-A1, HDL Apolipoprotein-A1, HDL-4 Apolipoprotein-A1 and HDL-4 Phospholipids. This study provides novel insights into the serum metabolic and lipoprotein subfraction changes in patients as they progress from a healthy state to MGUS to MM, which may allow for earlier clinical detection and treatment.

Novel dual-targeting c-Myc inhibitor D347-2761 represses myeloma growth via blocking c-Myc/Max heterodimerization and disturbing its stability

Background

Transcription factor c-Myc plays a critical role in various physiological and pathological events. c-Myc gene rearrangement is closely associated with multiple myeloma (MM) progression and drug resistance. Thereby, targeting c-Myc is expected to be a useful therapeutic strategy for hematological disease, especially in MM.

Methods

Molecular docking-based virtual screening and dual-luciferase reporter gene assay were used to identify novel c-Myc inhibitors. Cell viability and flow cytometry were performed for evaluating myeloma cytotoxicity. Western blot, immunofluorescence, immunoprecipitation, GST pull down and Electrophoretic Mobility Shift Assay were performed for protein expression and interaction between c-Myc and Max. c-Myc downstream targets were measured by Q-PCR and Chromatin immunoprecipitation methods. Animal experiments were used to detect myeloma xenograft and infiltration in vivo.

Results

We successfully identified a novel c-Myc inhibitor D347-2761, which hindered the formation of c-Myc/Max heterodimer and disturbed c-Myc protein stability simultaneously. Compound D347-2761 dose-and time-dependently inhibited myeloma cell proliferation and induced apoptosis. Dual knockout Bak/Bax partially restored D347-2761-mediated cell death. Additionally, compound D347-2761 could, in combination with bortezomib (BTZ), enhance MM cell DNA damage and overcome BTZ drug resistance. Our in vivo studies also showed that compound D347-2761 repressed myeloma growth and distal infiltration by downregulating c-Myc expression. Mechanistically, novel dual-targeting c-Myc inhibitor D347-2761 promoted c-Myc protein degradation via stimulating c-Myc Thr58 phosphorylation levels, which ultimately led to transcriptional repression of CDK4 promoter activity.

Conclusions

We identified a novel dual-targeting c-Myc small molecular inhibitor D347-2761. And this study may provide a solid foundation for developing a novel therapeutic agent targeting c-Myc.

Identification of High-Risk Multiple Myeloma With a Plasma Cell Leukemia-Like Transcriptomic Profile

Primary plasma cell leukemia (pPCL) is an aggressive subtype of multiple myeloma, which is distinguished from newly diagnosed multiple myeloma (NDMM) on the basis of the presence of ≥ 20% circulating tumor cells (CTCs). A molecular marker for pPCL is currently lacking, which could help identify NDMM patients with high-risk PCL-like disease, despite not having been recognized as such clinically.

Genomics of Plasma Cell Leukemia

Simple Summary

Plasma cell leukemia (PCL) is a very aggressive plasma cell disorder with a dismal prognosis, despite the therapeutic progress made in the last few years. The implementation of genomic high-throughput technologies in the clinical setting has revealed new insights into the genomic landscape of PCL, some of which may have an impact on the development of novel therapeutic approaches. The purpose of this review is to provide a comprehensive overview and update of the genomic studies carried out in PCL.

Abstract

Plasma cell leukemia (PCL) is a rare and highly aggressive plasma cell dyscrasia characterized by the presence of clonal circulating plasma cells in peripheral blood. PCL accounts for approximately 2–4% of all multiple myeloma (MM) cases. PCL can be classified in primary PCL (pPCL) when it appears de novo and in secondary PCL (sPCL) when it arises from a pre-existing relapsed/refractory MM. Despite the improvement in treatment modalities, the prognosis remains very poor. There is growing evidence that pPCL is a different clinicopathological entity as compared to MM, although the mechanisms underlying its pathogenesis are not fully elucidated. The development of new high-throughput technologies, such as microarrays and new generation sequencing (NGS), has contributed to a better understanding of the peculiar biological and clinical features of this disease. Relevant information is now available on cytogenetic alterations, genetic variants, transcriptome, methylation patterns, and non-coding RNA profiles. Additionally, attempts have been made to integrate genomic alterations with gene expression data. However, given the low frequency of PCL, most of the genetic information comes from retrospective studies with a small number of patients, sometimes leading to inconsistent results.

The Cytogenetic Profile of Primary and Secondary Plasma Cell Leukemia: Etiopathogenetic Perspectives, Prognostic Impact and Clinical Relevance to Newly Diagnosed Multiple Myeloma with Differential Circulating Clonal Plasma Cells

Plasma cell leukemia (PCL) is a rare and aggressive plasma cell dyscrasia that may appear as de-novo leukemia (pPCL) or on the basis of a pre-existing multiple myeloma (MM), called secondary plasma cell leukemia (sPCL). In this prospective study, we have applied a broad panel of FISH probes in 965 newly diagnosed MM (NDMM) and 44 PCL cases of both types to reveal the particular cytogenetic differences among the three plasma cell dyscrasias. In order to evaluate the frequency and patterns of clonal evolution, the same FISH panel was applied both at diagnosis and at the time of first relapse for 81 relapsed MM patients and both at MM diagnosis and during sPCL transformation for the 19 sPCL cases described here. pPCL was characterized by frequent MYC translocations and t(11;14) with a 11q13 breakpoint centered on the MYEOV gene, not commonly seen in MM. sPCL had a higher number of FISH abnormalities and was strongly associated with the presence of del(17p13), either acquired at the initial MM stage or as a newly acquired lesion upon leukemogenesis in the context of the apparent clonal evolution observed in sPCL. In clinical terms, sPCL showed a shorter overall survival than pPCL with either standard or high-risk (t(4;14) and/or t(14;16) and/or del(17p13) and/or ≥3 concomitant aberrations) abnormalities (median 5 months vs. 21 and 11 months respectively, p < 0.001), suggesting a prognostic stratification based on cytogenetic background. These observations proved relevant in the NDMM setting, where higher levels of circulating plasma cells (CPCs) were strongly associated with high-risk cytogenetics (median frequency of CPCs: 0.11% of peripheral blood nucleated cells for high-risk vs. 0.007% for standard-risk NDMM, p < 0.0001). Most importantly, the combined evaluation of CPCs (higher or lower than a cut-off of 0.03%), together with patients’ cytogenetic status, could be used for an improved prognostic stratification of NDMM patients.

Genetic profile of primary plasma cell leukemia in Korea: comparison with plasma cell myeloma

Plasma cell leukemia (PCL) is clinically and genetically distinct from multiple myeloma (MM), despite controversies regarding the disease definition. To determine the distinct features of PCL, the genetic property of primary PCL (pPCL) was compared with that of secondary PCL (sPCL) and MM. In patients with pPCL, Eighty-nine non-synonymous mutations were observed in 68 genes. The most frequently mutated genes were TP53, TSC2, and TYK2. In comparison with genetic abnormalities of sPCL and MM, 45 genes were present only in pPCL while 28 genes were only in sPCL and 22 genes only in MM. Among the common genes between pPCL and MM, a higher prevalence of TP53 was observed in pPCL, compared to MM (p < 0.05), while similar, compared to sPCL (p = 0.64). In summary, pPCL patients showed a higher level of genetic heterogeneity and distinctive genetic signature in their mutational profile compared to patients with MM and sPCL.

miR-22 Modulates Lenalidomide Activity by Counteracting MYC Addiction in Multiple Myeloma

Simple Summary

MYC-driven deregulation of microRNAs represents a critical event in human malignancies, including multiple myeloma (MM). Although the introduction of new therapeutic strategies has prolonged survival of patients, MM remains an incurable disease, often due to the onset of drug resistance. MYC hyperactivation is involved in the development of resistance to immunomodulatory imide drugs (IMiDs), but the mechanism is still unclear. Here, we report that MYC represses the transcription of tumor suppressor miR-22 in MM, and that low miR-22 expression is associated with IMiD resistance in MM patients. By in silico and in vitro analysis, we show that miR-22 mimics affect MYC signaling, leading to MM cell death in MYC proficient cells. Furthermore, we demonstrate here that lenalidomide treatment enhances miR-22 activity by reducing the MYC inhibitory effect, and that the combination of lenalidomide with miR-22 mimics restores drug sensitivity, leading to synergistic anti-MM activity.

Abstract

Background: MYC is a master regulator of multiple myeloma (MM) by orchestrating several pro-tumoral pathways, including reprograming of the miRNA transcriptome. MYC is also involved in the acquirement of resistance to anti-MM drugs, including immunomodulatory imide drugs (IMiDs). Methods: In silico analysis was performed on MM proprietary and on public MMRF-CoMMpass datasets. Western blot and chromatin immunoprecipitation (ChIP) experiments were performed to validate miR-22 repression induced by MYC. Cell viability and apoptosis assays were used to evaluate lenalidomide sensitization after miR-22 overexpression. Results: We found an inverse correlation between MYC and miR-22 expression, which is associated with poor outcome in IMiD-treated MM patients. Mechanistically, we showed that MYC represses transcription of miR-22, which, in turn, targets MYC, thus establishing a feed-forward loop. Interestingly, we found that IMiD lenalidomide increases miR-22 expression by reducing MYC repression and, most importantly, that the combination of lenalidomide with miR-22 mimics results in a synergistic direct and NK-mediated cytotoxic activity. Conclusions: Taken together, our findings indicate that: (1) low miR-22 expression could represent a potential predictive biomarker of poor lenalidomide response in MM patients; and (2) miR-22 reduces MYC oncogenic activity, thus triggering a novel synthetic lethality loop, which sensitizes MM cells to lenalidomide.

Plasma cell leukemia: A review of the molecular classification, diagnosis, and evidenced-based treatment

Plasma cell leukemia is a rare and aggressive plasma cell dyscrasia associated with dismal outcomes. It may arise de novo, primary plasma cell leukemia, or evolve from an antecedent diagnosis of multiple myeloma, secondary plasma cell leukemia. Despite highly effective therapeutics, survival for plasma cell leukemia patients remains poor. Molecular knowledge of plasma cell leukemia has recently expanded with use of gene expression profiling and whole exome sequencing, lending new insights into prognosis and therapeutic development. In this review, we describe the molecular knowledge, clinical characteristics, evidenced-based therapeutic approaches and treatment outcomes of plasma cell leukemia.

A clinical perspective on plasma cell leukemia; current status and future directions

Primary plasma cell leukemia (pPCL) is an aggressive plasma cell disorder with a guarded prognosis. The diagnosis is confirmed when peripheral blood plasma cells (PCs) exceed 20% of white blood cells or 2000/μL. Emerging data demonstrates that patients with lower levels of circulating (PCs) have the same adverse prognosis, challenging the clinical disease definition, but supporting the adverse impact of circulating PCs. The cornerstone of treatment consists of combination therapy incorporating a proteasome inhibitor, an immunomodulatory agent, steroids, and/or anthracyclines and alkylators as part of more-intensive chemotherapy, followed by consolidative autologous hematopoietic cell transplantation in eligible patients and then maintenance therapy. Monoclonal antibodies are also currently being evaluated in this setting with a strong rationale for their use based on their activity in multiple myeloma (MM). Due to limited therapeutic studies specifically evaluating pPCL, patients with pPCL should be considered for clinical trials. In contrast to MM, the outcomes of patients with pPCL have only modestly improved with novel therapies, and secondary PCL arising from MM in particular is associated with a dismal outlook. Newer drug combinations, immunotherapy, and cellular therapy are under investigation, and these approaches hopefully will demonstrate efficacy to improve the prognosis of pPCL.

Efficacy of Venetoclax and Dexamethasone in Refractory IgM Primary Plasma Cell Leukemia with t(11;14) and TP53 Mutation: A Case Report and Literature Review

Primary plasma cell leukemia (pPCL) is an uncommon disease. IgM multiple myeloma (MM) is an infrequent subtype that accounts for less than 1 percent of MM cases. IgM pPCL is quite rare with only a few cases published to date. We describe a case of a patient with IgM pPCL who initially presented with hyperviscosity syndrome requiring urgent plasma exchange. His bone marrow biopsy demonstrated t(11;14). He progressed on proteasome inhibitors, immunomodulating agents, and other chemotherapy medications but later achieved very good partial response (VGPR) to venetoclax and dexamethasone. Given the poor prognosis of pPCL, further studies using venetoclax alone or in combination with other novel agents as first-line treatment options are warranted particularly in patients with t(11;14).

Glucocorticoid receptor expression in multiple myeloma patients is a predictor of survival

Multiple myeloma (MM) is a blood neoplasia characterized by abnormal proliferation of plasma cells. Various treatments such as stem cell transplant (SCT), proteasome inhibitors, immune-modulating drugs, monoclonal antibodies and selective inhibitors of nuclear export have been routinely used to treat MM. However, relapse and treatment resistance are common problems in MM patients. Treatments are enhanced by Dexamethasone (Dex), a synthetic steroid that activates the glucocorticoid receptor (GR) which leads to apoptosis. To evaluate the potential impact of GR expression on overall survival, MM patient data from the CoMMpass study of 650 patients were analyzed. Multivariate modeling results show that increased GR expression at diagnosis is associated with a decreased risk of dying relative to those with lower levels of expression.

Hematopoietic cell transplantation utilization and outcomes for primary plasma cell leukemia in the current era

The outcomes of patients with primary plasma cell leukemia (pPCL) after undergoing hematopoietic cell transplantation (HCT) in the novel agent era are unknown. We report outcomes of 348 patients with pPCL receiving autologous (auto-) HCT (n = 277) and allogeneic (allo-) HCT (n = 71) between 2008 and 2015. Median age was 60 years and 56 years for auto- and allo-HCT respectively. For auto-HCT, the 4-year outcomes were: non-relapse mortality (NRM) 7% (4-11%), relapse (REL) 76% (69-82%), progression-free survival (PFS) 17% (13-23%), and overall survival (OS) 28% (22-35%). Karnofsky performance status (KPS) > 90 and ≥very good partial response (VGPR) predicted superior OS in multi-variate analysis for auto-HCT. For allo-HCT, the 4-year outcomes were: NRM 12% (5-21%), REL 69% (56-81%), PFS 19% (10-31%), and OS 31% (19-44%). Compared with prior CIBMTR pPCL patients (1995-2006), inferior survival was noted in the current cohort (3-year OS, 39% vs. 38% in allo-HCT, and 62% vs. 35% in auto-HCT) respectively. However, we noted an increased HCT utilization, from 12% (7-21%) in 1995 to 46% (34-64%) in 2009 using SEER data (available till 2009). Despite modern induction translating to higher proportion receiving HCT, the outcomes remain poor in pPCL patients, mainly derived by high relapse rates post-HCT.

The Non-Coding RNA Landscape of Plasma Cell Dyscrasias

Despite substantial advancements have been done in the understanding of the pathogenesis of plasma cell (PC) disorders, these malignancies remain hard-to-treat. The discovery and subsequent characterization of non-coding transcripts, which include several members with diverse length and mode of action, has unraveled novel mechanisms of gene expression regulation often malfunctioning in cancer. Increasing evidence indicates that such non-coding molecules also feature in the pathobiology of PC dyscrasias, where they are endowed with strong therapeutic and/or prognostic potential. In this review, we aim to summarize the most relevant findings on the biological and clinical features of the non-coding RNA landscape of malignant PCs, with major focus on multiple myeloma. The most relevant classes of non-coding RNAs will be examined, along with the mechanisms accounting for their dysregulation and the recent strategies used for their targeting in PC dyscrasias. It is hoped these insights may lead to clinical applications of non-coding RNA molecules as biomarkers or therapeutic targets/agents in the near future.

MYC amplification on double minute chromosomes in plasma cell leukemia with double IGH/CCND1 fusion genes

In multiple myeloma (MM), MYC rearrangements that result in increased MYC expression are associated with an aggressive form of MM and adverse outcome. However, the consequences of MYC amplification in MM remain unclear. Here, we describe an unusual case of plasma cell leukemia (PCL) harboring MYC amplification on double minute chromosomes (dmin). A 79-year-old woman was initially diagnosed as having BJP-κ type MM with bone lesions. After seven months, the disease progressed to secondary PCL: leukocytes 49.1 × 10⁹/L with 77% plasma cells showing lymphoplasmacytic appearance. The bone marrow was infiltrated with 76% plasma cells immunophenotypically positive for CD38 and negative for CD45, CD19, CD20, and CD56. The karyotype by G-banding and spectral karyotyping was 48,XX,der(14)t(11;14)(q13;q32),+der(14)t(14;19)(q32;q13.1),+18,6~95dmin[15]/46,XX[5]. Fluorescence in situ hybridization detected multiple MYC signals on dmin and double IGH/CCND1 fusion signals on der(14)t(11;14) and der(14)t(14;19). Most plasma cells were diffusely and strongly positive for MYC and CCND1 by immunohistochemistry. The patient died of progressive disease after one week. MYC amplification led to high expression of MYC and rapid disease progression, indicating its clinical significance in the pathogenesis of MM/PCL. MYC amplification on dmin may be a very rare genetic event closely associated with the progression to PCL and coexistence of IGH/CCND1 fusions.

An update on biology, diagnosis and treatment of primary plasma cell leukemia

INTRODUCTION

Primary plasma cell leukemia (PPCL) is one of the most aggressive hematological malignancies. The prognosis of PPCL patients remains poor, although some improvements have been made in recent years. Areas covered: In this review recent clinical and biological advances in PPCL are reported. Some recommendations for the practical management of these patients are provided, with a particular focus on the role of novel agents and transplant procedures. A brief description of the currently ongoing clinical trials with new drugs is also enclosed. Expert opinion: PPCL still represents a difficult challenge for all hematologists. Here the authors provide a personal view on how the current, generally unsatisfactory results in this neoplastic disorder could be improved. In particular, dedicated studies exploring alternative therapies are necessary and eagerly awaited. Such studies should possibly be based on new biological information that could be of help in identifying novel genetic biomarkers for risk stratification and new actionable molecular targets.

Plasma Cell Leukemia: Definition, Presentation, and Treatment

Purpose of Review

We discuss current topics on the definition of plasma cell leukemia and the distinction between plasma cell leukemia and multiple myeloma. Moreover, we review the latest literature on how to treat plasma cell leukemia.

Recent Findings

Plasma cell leukemia is clinically and genetically distinct from multiple myeloma. Plasma cell leukemia is defined by the observation in blood of more than 20% clonal plasma cells by differential count of the leucocytes or by counting more than 2 × 10⁹ per liter circulating clonal plasma cells. However, patients with lower levels of circulating plasma cells have the same adverse prognosis, which challenges the disease definition. Survival has improved after implementation of high-dose chemotherapy with stem-cell support, bortezomib, and lenalidomide in the treatment; yet, the prognosis remains poor. The results of allo-transplants have been disappointing.

Summary

The diagnostic criteria of PCL are currently discussed in the international myeloma community. Despite some improvement in survival, the prognosis remains adverse. New, more targeted treatment modalities, including immunotherapies, will hopefully improve the outcome in the near future.

The Role of c-MYC in B-Cell Lymphomas: Diagnostic and Molecular Aspects

c-MYC is one of the most essential transcriptional factors, regulating a diverse array of cellular functions, including proliferation, growth, and apoptosis. Dysregulation of c-MYC is essential in the pathogenesis of a number of B-cell lymphomas, but is rarely reported in T-cell lymphomas. c-MYC dysregulation induces lymphomagenesis by loss of the tight control of c-MYC expression, leading to overexpression of intact c-MYC protein, in contrast to the somatic mutations or fusion proteins seen in many other oncogenes. Dysregulation of c-MYC in B-cell lymphomas occurs either as a primary event in Burkitt lymphoma, or secondarily in aggressive lymphomas such as diffuse large B-cell lymphoma, plasmablastic lymphoma, mantle cell lymphoma, or double-hit lymphoma. Secondary c-MYC changes include gene translocation and gene amplification, occurring against a background of complex karyotype, and most often confer aggressive clinical behavior, as evidenced in the double-hit lymphomas. In low-grade B-cell lymphomas, acquisition of c-MYC rearrangement usually results in transformation into highly aggressive lymphomas, with some exceptions. In this review, we discuss the role that c-MYC plays in the pathogenesis of B-cell lymphomas, the molecular alterations that lead to c-MYC dysregulation, and their effect on prognosis and diagnosis in specific types of B-cell lymphoma.

Therapy for Relapsed Multiple Myeloma: Guidelines From the Mayo Stratification for Myeloma and Risk-Adapted Therapy

Life expectancy in patients with multiple myeloma is increasing because of the availability of an increasing number of novel agents with various mechanisms of action against the disease. However, the disease remains incurable in most patients because of the emergence of resistant clones, leading to repeated relapses of the disease. In 2015, 5 novel agents were approved for therapy for relapsed multiple myeloma. This surfeit of novel agents renders management of relapsed multiple myeloma more complex because of the occurrence of multiple relapses, the risk of cumulative and emergent toxicity from previous therapies, as well as evolution of the disease during therapy. A group of physicians at Mayo Clinic with expertise in the care of patients with multiple myeloma regularly evaluates the evolving literature on the biology and therapy for multiple myeloma and issues guidelines on the optimal care of patients with this disease. In this article, the latest recommendations on the diagnostic evaluation of relapsed multiple myeloma and decision trees on how to treat patients at various stages of their relapse (off study) are provided together with the evidence to support them.

p53 dysregulation in B-cell malignancies: More than a single gene in the pathway to hell

TP53 deletion or mutation is frequent in B-cell malignancies and is associated with a low response rate. We describe here the p53 landscape in B-cell malignancies, from B-Acute Lymphoblastic Leukemia to Plasma Cell Leukemia, by analyzing incidence of gain or loss of function of actors both upstream and within the p53 pathway, namely MYC, RAS, ARF, MDM2, ATM and TP53. Abnormalities are not equally distributed and their incidence is highly variable among malignancies. Deletion and mutation, usually associated, of ATM or TP53 are frequent in Diffuse Large B-Cell Lymphoma and Mantle Cell Lymphoma. MYC gain, absent in post-GC malignancies, is frequent in B-Prolymphocytic-Leukemia, Multiple Myeloma and Plasma Cell Leukemias. RAS mutations are rare except in MM and PCL. Multiple Factorial Analysis notes that MYC deregulation is closely related to TP53 status. Moreover, MYC gain, TP53 deletion and RAS mutations are inversely correlated with survival. Based on this landscape, we further propose targeted therapeutic approaches for the different B-cell malignancies.

Whole-exome sequencing of primary plasma cell leukemia discloses heterogeneous mutational patterns

Primary plasma cell leukemia (pPCL) is a rare and aggressive form of plasma cell dyscrasia and may represent a valid model for high-risk multiple myeloma (MM). To provide novel information concerning the mutational profile of this disease, we performed the whole-exome sequencing of a prospective series of 12 pPCL cases included in a Phase II multicenter clinical trial and previously characterized at clinical and molecular levels. We identified 1, 928 coding somatic non-silent variants on 1, 643 genes, with a mean of 166 variants per sample, and only few variants and genes recurrent in two or more samples. An excess of C > T transitions and the presence of two main mutational signatures (related to APOBEC over-activity and aging) occurring in different translocation groups were observed. We identified 14 candidate cancer driver genes, mainly involved in cell-matrix adhesion, cell cycle, genome stability, RNA metabolism and protein folding. Furthermore, integration of mutation data with copy number alteration profiles evidenced biallelically disrupted genes with potential tumor suppressor functions. Globally, cadherin/Wnt signaling, extracellular matrix and cell cycle checkpoint resulted the most affected functional pathways. Sequencing results were finally combined with gene expression data to better elucidate the biological relevance of mutated genes. This study represents the first whole-exome sequencing screen of pPCL and evidenced a remarkable genetic heterogeneity of mutational patterns. This may provide a contribution to the comprehension of the pathogenetic mechanisms associated with this aggressive form of PC dyscrasia and potentially with high-risk MM.

Bortezomib, Doxorubicin, Cyclophosphamide, Dexamethasone Induction Followed by Stem Cell Transplantation for Primary Plasma Cell Leukemia: A Prospective Phase II Study of the Intergroupe Francophone du Myélome

PURPOSE

Primary plasma cell leukemia (pPCL) is a rare and aggressive malignancy with a poor prognosis. With conventional chemotherapy, patients typically die within 1 year. In all but one of the retrospective studies reported to date, bortezomib and lenalidomide seem to improve survival. We conducted a prospective phase II trial in patients with pPCL to assess the efficacy of an alternate regimen that combines standard chemotherapy, a proteasome inhibitor, and high-dose melphalan and autologous stem cell transplantation (HDM/ASCT) followed by either allogeneic transplantation or bortezomib/lenalidomide maintenance.

PATIENTS AND METHODS

Patients 70 years old and younger with newly diagnosed pPCL received four alternating cycles of bortezomib, dexamethasone plus doxorubicin or cyclophosphamide. Peripheral blood stem cells were collected from responding patients with < 1% of circulating plasma cells before HDM/ASCT. As consolidation, young patients received a reduced-intensity conditioning allograft, whereas the remaining patients underwent a second HDM/ASCT followed by 1 year of bortezomib, lenalidomide, dexamethasone. The primary end point was progression-free survival (PFS).

RESULTS

Forty patients (median age, 57 years; range, 27 to 71 years) were enrolled. The median follow-up was 28.7 months. In the intention-to-treat analysis, the median PFS and overall survival were 15.1 (95% CI, 8.4; -) and 36.3 (95% CI, 25.6; -) months, respectively. The overall response rate to induction was 69%. One patient underwent a syngeneic allograft and 25 HDM/ASCT (16 of whom subsequently received a reduced-intensity conditioning allograft and seven a second ASCT followed by maintenance).

CONCLUSION

In this prospective trial in patients with pPCL, we show that bortezomib, dexamethasone plus doxorubicin or cyclophosphamide induction followed by transplantation induces high response rates and appears to significantly improve PFS.

Primary plasma cell leukaemia in a 22-year-old woman: A case report

Introduction

Primary plasma cell leukaemia is a rare and highly aggressive disease that is commonly diagnosed a decade earlier than multiple myeloma, at a median age of 55 years. However, it has also been described in younger patients, as documented in this case report. It often presents with hepatosplenomegaly and lymphadenopathy, whilst the presence of bony lesions are less-commonly seen when compared to multiple myeloma.

Case presentation

This report describes the case of a young woman who presented with symptoms of anaemia and a history of menorrhagia. On further careful examination, she was found to have additional signs and symptoms and was later diagnosed with primary plasma cell leukaemia.

Management and outcome

On admission, the patient received supportive care measures, including blood products. At diagnosis, a specific chemotherapy regimen was commenced; however, this failed to induce remission. The decision to continue with supportive care only was made and the patient died seven months later.

Discussion

This case study is presented because of its rarity, the young age of the patient at presentation and the unusual clinical and laboratory findings. Persistent anaemia unresponsive to standard treatment should raise the index of suspicion and further investigations directed to exclude malignancies should be considered.

Molecular Classification and Pharmacogenetics of Primary Plasma Cell Leukemia: An Initial Approach toward Precision Medicine

Primary plasma cell leukemia (pPCL) is a rare and aggressive variant of multiple myeloma (MM) which may represent a valid model for high-risk MM. This disease is associated with a very poor prognosis, and unfortunately, it has not significantly improved during the last three decades. New high-throughput technologies have allowed a better understanding of the molecular basis of this disease and moved toward risk stratification, providing insights for targeted therapy studies. This knowledge, added to the pharmacogenetic profile of new and old agents in the analysis of efficacy and safety, could contribute to help clinical decisions move toward a precision medicine and a better clinical outcome for these patients. In this review, we describe the available literature concerning the genomic characterization and pharmacogenetics of plasma cell leukemia (PCL).

Chromosome 8q24.1/c-MYC abnormality: a marker for high-risk myeloma

The proto-oncogene c-MYC is rearranged in about 15% of patients with multiple myeloma (MM). We identified 23 patients with MM and c-MYC. Primary objectives were to describe the clinical characteristics, response to therapy, progression-free survival and overall survival (OS). Twelve out of twenty-three patients presented with or progressed to either plasma cell leukemia (PCL) and/or extramedullary disease (EMD). Induction therapy consisted of an immunomodulatory, proteasome inhibitor-based or conventional chemotherapy regimen. Fifteen patients achieved a partial response and three achieved a very good partial response. Sixteen patients received an autologous and one patient an allogeneic hematopoietic stem cell transplant. Median OS from diagnosis was 20.2 months. Patients with PCL or EMD had significantly shorter OS (15.5 vs. 40.4 months, p = 0.0005). This is the first report describing the clinical characteristics of patients with MM and c-MYC. These abnormalities are associated with an aggressive form of MM, high incidence of PCL/EMD and short OS.

Translocations at 8q24 juxtapose MYC with genes that harbor superenhancers resulting in overexpression and poor prognosis in myeloma patients

Secondary MYC translocations in myeloma have been shown to be important in the pathogenesis and progression of disease. Here, we have used a DNA capture and massively parallel sequencing approach to identify the partner chromosomes in 104 presentation myeloma samples. 8q24 breakpoints were identified in 21 (20%) samples with partner loci including IGH, IGK and IGL, which juxtapose the immunoglobulin (Ig) enhancers next to MYC in 8/23 samples. The remaining samples had partner loci including XBP1, FAM46C, CCND1 and KRAS, which are important in B-cell maturation or myeloma pathogenesis. Analysis of the region surrounding the breakpoints indicated the presence of superenhancers on the partner chromosomes and gene expression analysis showed increased expression of MYC in these samples. Patients with MYC translocations had a decreased progression-free and overall survival. We postulate that translocation breakpoints near MYC result in colocalization of the gene with superenhancers from loci, which are important in the development of the cell type in which they occur. In the case of myeloma these are the Ig loci and those important for plasma cell development and myeloma pathogenesis, resulting in increased expression of MYC and an aggressive disease phenotype.

Promiscuous MYC locus rearrangements hijack enhancers but mostly super-enhancers to dysregulate MYC expression in multiple myeloma

MYC locus rearrangements – often complex combinations of translocations, insertions, deletions, and inversions - in multiple myeloma (MM) were thought to be a late progression event, which often did not involve immunoglobulin genes. Yet germinal center activation of MYC expression has been reported to cause progression to MM in an MGUS prone mouse strain. Although previously detected in 16% of MM, we find MYC rearrangements in nearly 50% of MM, including smoldering MM, and they are heterogeneous in some cases. Rearrangements reposition MYC near a limited number of genes associated with conventional enhancers, but mostly with super-enhancers (e.g., IGH, IGL, IGK, NSMCE2, TXNDC5, FAM46C, FOXO3, IGJ, PRDM1). MYC rearrangements are associated with a significant increase of MYC expression that is monoallelic, but MM tumors lacking a rearrangement have bi-allelic MYC expression at significantly higher levels than in MGUS. We also show that germinal center activation of MYC does not cause MM in a mouse strain that rarely develops spontaneous MGUS. It appears that increased MYC expression at the MGUS/MM transition usually is bi-allelic, but sometimes can be mono-allelic if there is a MYC rearrangement. Our data suggests that MYC rearrangements, regardless of when they occur during MM pathogenesis, provide one event that contributes to tumor autonomy.

Plasma cell enrichment enhances detection of high-risk cytogenomic abnormalities by fluorescence in situ hybridization and improves risk stratification of patients with plasma cell neoplasms

CONTEXT

Methods for plasma cell enrichment of bone marrow (BM) specimens can increase the sensitivity of fluorescence in situ hybridization (FISH) for detecting cytogenomic abnormalities. There are no published reports using these methods to evaluate high-risk cytogenomic abnormalities in patients with plasma cell neoplasms (PCNs) after therapy.

OBJECTIVE

To evaluate the utility of plasma cell enrichment combined with FISH for detection of high-risk cytogenomic abnormalities in patients with PCNs after therapy.

DESIGN

Twenty-eight patients with PCNs, of whom 22 received treatment, were included in this study. Plasma cells were enriched in BM aspirates by using a magnetic cell-sorting procedure to select CD138(+) cells. Probes were chosen to assess for del(17p13/TP53), del(13q14/RB1), 1q21/CKS1B gain, IgH/FGFR3, and IgH/MAF. Clinicopathologic data were collected during clinical follow-up after plasma cell enrichment.

RESULTS

Plasma cells in nonenriched BM specimens ranged from 1% to 28% (median, 8%) compared with 28% to 96% (median, 73%) in enriched BM specimens (P < .001). In a subset of treated patients in clinical remission, FISH detected high-risk cytogenomic abnormalities only in plasma cell-enriched samples. This approach also detected abnormalities in cases of solitary plasmacytoma and monoclonal gammopathy of undetermined significance.

CONCLUSIONS

Plasma cell enrichment of BM specimens increases FISH sensitivity for detecting high-risk cytogenomic abnormalities, particularly in treated patients, and these results, in combination with clinical follow-up data, can be of value to improve risk stratification and patient management.

Biological and clinical relevance of miRNA expression signatures in primary plasma cell leukemia

PURPOSE

Primary plasma cell leukemia (pPCL) is a rare and very aggressive form of plasma cell dyscrasia. To date, no information on microRNA (miRNA) expression in pPCL has been reported. This study aimed at investigating the involvement of miRNAs in pPCL and their possible relationship with higher tumor aggressiveness.

EXPERIMENTAL DESIGN

Global miRNA expression profiles were analyzed in highly purified malignant plasma cells from 18 pPCL untreated patients included in a prospective clinical trial. MiRNA expression patterns were evaluated in comparison with a representative series of multiple myeloma patients, in relation to the most recurrent chromosomal abnormalities (as assessed by fluorescence in situ hybridization and single-nucleotide polymorphism-array analysis), and in association with clinical outcome. MiRNA expression was also integrated with gene expression profiles in pPCL and multiple myeloma samples.

RESULTS

We identified a series of deregulated miRNAs in pPCL (42 upregulated and 41 downregulated) in comparison with multiple myeloma. Some of them, on the basis of their reported functions and putative target genes computed by integrative analysis, might have a role in the pathobiology of pPCL. As regards chromosomal aberrations, the expression of some miRNAs mapped to hotspot altered regions was associated with DNA copy number of the corresponding loci. Finally, 4 miRNA (miR-497, miR-106b, miR-181a*, and miR-181b) were identified as having expression levels that correlated with treatment response, and 4 (miR-92a, miR-330-3p, miR-22, and miR-146a) with clinical outcome.

CONCLUSIONS

Overall, our study provides insights into the possible contribution of miRNAs in the pathogenesis of pPCL and suggests targets for future therapeutic investigations.

Genome-wide analysis of primary plasma cell leukemia identifies recurrent imbalances associated with changes in transcriptional profiles

Primary plasma cell leukemia (pPCL) is a rare, yet aggressive form of de novo plasma cell tumor, distinct from secondary PCL (sPCL) which represents a leukemic transformation of pre-existing multiple myeloma (MM). Herein, we performed a comprehensive molecular analysis of a prospective series of pPCLs by means of FISH, single nucleotide polymorphism (SNP) array and gene expression profiling (GEP). IGH@ translocations were identified in 87% of pPCL cases, with prevalence of t(11;14) (40%) and t(14;16) (30.5%), whereas the most frequent numerical alterations involved 1p (38%), 1q (48%), 6q (29%), 8p (42%), 13q (74%), 14q (71%), 16q (53%), and 17p (35%). We identified a minimal biallelic deletion (1.5 Mb) in 8p21.2 encompassing the PPP2R2A gene, belonging to a family of putative tumor suppressors and found to be significantly down-regulated in deleted cases. Mutations of TP53 were identified in four cases, all but one associated with a monoallelic deletion of the gene, whereas activating mutations of the BRAF oncogene occurred in one case and were absent in N- and K-RAS. To evaluate the influence of allelic imbalances in transcriptional expression we performed an integrated genomic analysis with GEP data, showing a significant dosage effect of genes involved in transcription, translation, methyltransferase activity, apoptosis as well as Wnt and NF-kB signaling pathways. Overall, we provide a compendium of genomic alterations in a prospective series of pPCLs which may contribute to improve our understanding of the pathogenesis of this aggressive form of plasma cell dyscrasia and the mechanisms of tumor progression in MM.

Plasma cell leukemia: consensus statement on diagnostic requirements, response criteria and treatment recommendations by the International Myeloma Working Group

Plasma cell leukemia (PCL) is a rare and aggressive variant of myeloma characterized by the presence of circulating plasma cells. It is classified as either primary PCL occurring at diagnosis or as secondary PCL in patients with relapsed/refractory myeloma. Primary PCL is a distinct clinic-pathological entity with different cytogenetic and molecular findings. The clinical course is aggressive with short remissions and survival duration. The diagnosis is based upon the percentage (≥ 20%) and absolute number (≥ 2 × 10(9)/l) of plasma cells in the peripheral blood. It is proposed that the thresholds for diagnosis be re-examined and consensus recommendations are made for diagnosis, as well as, response and progression criteria. Induction therapy needs to begin promptly and have high clinical activity leading to rapid disease control in an effort to minimize the risk of early death. Intensive chemotherapy regimens and bortezomib-based regimens are recommended followed by high-dose therapy with autologous stem cell transplantation if feasible. Allogeneic transplantation can be considered in younger patients. Prospective multicenter studies are required to provide revised definitions and better understanding of the pathogenesis of PCL.

Clinical features and outcomes of plasma cell leukemia: a single-institution experience in the era of novel agents

Plasma cell leukemia (PCL) is a rare hematologic malignancy with aggressive clinical and biologic features. Data regarding its prognosis with the use of the novel agents, i.e., the immunomodulatory drugs thalidomide and lenalidomide, and the proteasome inhibitor bortezomib, are limited. We retrospectively reviewed clinical outcomes, response to therapy, and survival of 17 patients seen at the Penn State Hershey Cancer Institute since the availability of novel agents (2006–2011). Twelve patients had primary PCL (pPCL), and 5 secondary PCL (sPCL). PCL was associated with aggressive clinicobiological features, such as high-risk cytogenetics, elevated serum beta-2-microglobulin and lactate dehydrogenase, International Staging System stage III, and rapid relapse after therapy. With the use of thalidomide, lenalidomide, and bortezomib in 53%, 53%, and 88% patients, respectively, median overall survival (OS) was 18 months in the whole group (95% confidence interval, 11–21 months), and 21 and 4 months in pPCL and sPCL, respectively (P=0.015). OS was inferior to that of 313 consecutive patients with multiple myeloma (MM) treated in the same period, even when compared with a subset of 47 MM with high-risk cytogenetics. Although our data are limited by the small sample size, we conclude that novel agents may modestly improve survival in patients with PCL, when compared to historical controls. Novel therapies do not seem to overcome the negative prognosis of PCL as compared with MM.

How I treat plasma cell leukemia

Primary plasma cell leukemia (pPCL) is a rare and aggressive plasma cell proliferative disorder with a very poor prognosis and with distinct biologic, clinical, and laboratory features. Compared with multiple myeloma, pPCL presents more often with extramedullary involvement, anemia, thrombocytopenia, hypercalcemia, elevated serum β(2)-microglobulin and lactate dehydrogenase levels, as well as impaired renal function. Many of the genetic aberrations observed in newly diagnosed pPCL are typically found in advanced multiple myeloma. These cytogenetic abnormalities and mutations lead to increased proliferation, enhanced inhibition of apoptosis, escape from immune surveillance, and independence from the BM microenvironment, with changes in expression of adhesion molecules or chemokine receptors. The outcome of pPCL has improved with the introduction of autologous stem cell transplantation and combination approaches with novel agents, including bortezomib and immunomodulatory drugs, such as lenalidomide. In this review, we provide an overview of currently available therapeutic options with recommendations of how these treatment modalities can best be used to improve outcome for plasma cell leukemia patients.

Cytotoxicity, anti-angiogenic, apoptotic effects and transcript profiling of a naturally occurring naphthyl butenone, guieranone A

Background

Malignant diseases are responsible of approximately 13% of all deaths each year in the world. Natural products represent a valuable source for the development of novel anticancer drugs. The present study was aimed at evaluating the cytotoxicity of a naphtyl butanone isolated from the leaves of Guiera senegalensis, guieranone A (GA).

Results

The results indicated that GA was active on 91.67% of the 12 tested cancer cell lines, the IC₅₀ values below 4 μg/ml being recorded on 83.33% of them. In addition, the IC₅₀ values obtained on human lymphoblastic leukemia CCRF-CEM (0.73 μg/ml) and its resistant subline CEM/ADR5000 (1.01 μg/ml) and on lung adenocarcinoma A549 (0.72 μg/ml) cell lines were closer or lower than that of doxorubicin. Interestingly, low cytotoxicity to normal hepatocyte, AML12 cell line was observed. GA showed anti-angiogenic activity with up to 51.9% inhibition of the growth of blood capillaries on the chorioallantoic membrane of quail embryo. Its also induced apotosis and cell cycle arrest. Ingenuity Pathway Analysis identified several pathways in CCRF-CEM cells and functional group of genes regulated upon GA treatment (P < 0.05), the Cell Cycle: G2/M DNA Damage Checkpoint Regulation and ATM Signaling pathways being amongst the four most involved functional groups.

Conclusion

The overall results of this work provide evidence of the cytotoxic potential of GA and supportive data for its possible use in cancer chemotherapy.

Myc roles in hematopoiesis and leukemia

Hematopoiesis is a process capable of generating millions of cells every second, as distributed in many cell types. The process is regulated by a number of transcription factors that regulate the differentiation along the distinct lineages and dictate the genetic program that defines each mature phenotype. Myc was first discovered as the oncogene of avian leukemogenic retroviruses; it was later found translocated in human lymphoma. From then on, evidence accumulated showing that c-Myc is one of the transcription factors playing a major role in hematopoiesis. The study of genetically modified mice with overexpression or deletion of Myc has shown that c-Myc is required for the correct balance between self-renewal and differentiation of hematopoietic stem cells (HSCs). Enforced Myc expression in mice leads to reduced HSC pools owing to loss of self-renewal activity at the expense of increased proliferation of progenitor cells and differentiation. c-Myc deficiency consistently results in the accumulation of HSCs. Other models with conditional Myc deletion have demonstrated that different lineages of hematopoietic cells differ in their requirement for c-Myc to regulate their proliferation and differentiation. When transgenic mice overexpress c-Myc or N-Myc in mature cells from the lymphoid or myeloid lineages, the result is lymphoma or leukemia. In agreement, enforced expression of c-Myc blocks the differentiation in several leukemia-derived cell lines capable of differentiating in culture. Not surprising, MYC deregulation is recurrently found in many types of human lymphoma and leukemia. Whereas MYC is deregulated by translocation in Burkitt lymphoma and, less frequently, other types of lymphoma, MYC is frequently overexpressed in acute lymphoblastic and myeloid leukemia, through mechanisms unrelated to chromosomal translocation, and is often associated with disease progression.

Plasma cell myeloma and related neoplasms

Session 1 of the 2009 Workshop of the Society for Hematopathology/European Association of Haematopathology, Cleveland, OH, focused on plasma cell neoplasms. This report summarizes the salient diagnostic, clinical, and genetic features of plasma cell myeloma (PCM) and related neoplasms. Based on the cases submitted to the workshop, we highlight common diagnostic issues and unusual manifestations of plasma cell neoplasms, such as t(11;14)+ PCM, plasma cell leukemia, and nonsecretory plasmacytoma, as well as plasmablastic transformation of PCM. Additional issues repeatedly raised at the workshop included the differential diagnosis of extramedullary dissemination of PCM vs primary extramedullary plasmacytoma and plasmablastic lymphoma; systemic plasma cell neoplasms in immunocompromised people; and Epstein-Barr virus-associated plasma cell neoplasms. Difficult cases with borderline features presented by submitters emphasized the necessity of integrating clinical, immunophenotypic, and genetic features for appropriate classification of these disorders.

Primary plasma cell leukemia in the era of new drugs: has something changed?

Primary plasma cell leukemia (PPCL) is a rare and aggressive variant of multiple myeloma. This disease is associated with a very poor prognosis, and unfortunately it has not significantly improved during the last three decades. Autologous stem cell transplantation is generally recommended in eligible patients, but survival in transplanted PPCL patients is significantly lower than that of multiple myeloma. Recent preliminary data indicate that new drugs, in particular lenalidomide and bortezomib, could significantly improve the clinical outcome of PPCL, increasing response rate and duration, as well as survival. In this review we report an updated literature analysis about the current therapeutic scenario of PPCL, with a particular focus on the use of novel agents.

Correlation of assessment of plasma cells by flow cytometry and detection of cytogenomic abnormalities by fluorescence in situ hybridization in plasma cell neoplasms

INTRODUCTION

Increased monoclonal plasma cell count (PCC) in bone marrow (BM) is an indicator of a plasma cell neoplasm (PCN). Assessing PCC in BM by morphologic evaluation (ME) and flow cytometry (FC) is important in diagnosing PCN. Also important is fluorescence in situ hybridization (FISH) to detect cytogenomic abnormalities (CAs) in PCN. Owing to FC's short turnaround time, FC-assessed PCC is often used as empirical reference for further FISH study. However, correlation of FC-assessed PCs with FISH-detected CAs has not been well studied. The purpose of this study was to validate this correlation on BM aspirates from patients with PCN.

METHODS

We reviewed 224 cases of newly diagnosed PCN identified from our Lab-database. Both FC and FISH had been performed on BM aspirates from these cases, of which 178 had been assessed by ME. The original findings from the 224 cases were also reviewed.

RESULTS

Using a cut-off of 3% PCs assessed by FC as an indicator for further FISH analysis, 20 (17%) FISH-detectable PCN cases were missed; 30% of the missed cases carried high-risk CAs and/or were highly progressive PCN.

CONCLUSION

In PCN cases, an FC-assessed 3% PCC in BM aspirates should not be used as a cut-off for further FISH testing.

Role of triptolide in cell proliferation, cell cycle arrest, apoptosis and histone methylation in multiple myeloma U266 cells

Multiple myeloma is an incurable hematological malignancy. Different studies demonstrated the occurrence of genetic and epigenetic alterations in multiple myeloma. Histone lysine methylation has emerged as a central epigenetic change in the organization of eukaryotic chromatin with far-reaching implications for the regulation of cell proliferation, cell-type differentiation, gene expression, genome stability, overall development, and genesis of cancer. Triptolide is the principal active ingredient in extracts from the Chinese herb Tripterygium wilfordii Hook.F (TwHF), and numerous studies have elucidated its antitumor property. Our experiments discovered that triptolide inhibited the proliferation of multiple myeloma cell line U266 in a time- and dose-dependent manner, induced G2/M cell cycle arrest and caspase-dependent apoptosis. Triptolide could decrease the expression of histone H3K4, H3K27 and H3K36 trimethylation in parallel with histone methyltransferases SMYD3, EZH2 and NSD1 respectively, which possibly was the anti-myeloma mechanism of triptolide.

Systemic joint laxity and mandibular range of movement

Primary plasma cell leukemia (pPCL) is a rare and aggressive form of multiple myeloma (MM) that is characterized by the presence of ≥20% circulating plasma cells. Overall survival remains poor despite advances of anti-MM therapy. The disease biology as well as molecular mechanisms that distinguish pPCL from non-pPCL MM remain poorly understood and, given the rarity of the disease, are challenging to study. In an attempt to identify key biological mechanisms that result in the aggressive pPCL phenotype, we performed whole-exome sequencing and gene expression analysis in 23 and 41 patients with newly diagnosed pPCL, respectively. The results reveal an enrichment of complex structural changes and high-risk mutational patterns in pPCL that explain, at least in part, the aggressive nature of the disease. In particular, pPCL patients with traditional low-risk features such as translocation t(11;14) or hyperdiploidy accumulated adverse risk genetic events that could account for the poor outcome in this group. Furthermore, gene expression profiling showed upregulation of adverse risk modifiers in pPCL compared to non-pPCL MM, while adhesion molecules and extracellular matrix proteins became increasingly downregulated. In conclusion, this is one of the largest studies to dissect pPCL on a genomic and molecular level.