Molecular pathogenesis of multiple myeloma: basic and clinical updates

The biological and clinical impact of deletions before and after large chromosomal gains in multiple myeloma

ABSTRACT

Acquisition of a hyperdiploid (HY) karyotype or immunoglobulin heavy chain (IgH) translocations are considered key initiating events in multiple myeloma (MM). To explore if other genomic events can precede these events, we analyzed whole-genome sequencing data from 1173 MM samples. By integrating molecular time and structural variants within early chromosomal duplications, we indeed identified pregain deletions in 9.4% of patients with an HY karyotype without IgH translocations, challenging acquisition of an HY karyotype as the earliest somatic event. Remarkably, these deletions affected tumor suppressor genes (TSGs) and/or oncogenes in 2.4% of patients with an HY karyotype without IgH translocations, supporting their role in MM pathogenesis. Furthermore, our study points to postgain deletions as novel driver mechanisms in MM. Using multiomics approaches to investigate their biologic impact, we found associations with poor clinical outcome in newly diagnosed patients and profound effects on both the oncogene and TSG activity despite the diploid gene status. Overall, this study provides novel insights into the temporal dynamics of genomic alterations in MM.

TGF-β: an active participant in the immune and metabolic microenvironment of multiple myeloma : TGF-β in the microenvironment of multiple myeloma

Although substantial quantities of potent therapies for multiple myeloma (MM) have been established, MM remains an incurable disease. In recent years, our understanding of the initiation, development, and metastasis of cancers has made a qualitative leap. Cancers attain the abilities to maintain proliferation signals, escape growth inhibitors, resist cell death, induce angiogenesis, and more importantly, escape anti-tumor immunity and reprogram metabolism, which are the hallmarks of cancers. Besides, different cancers have different tumor microenvironments (TME), thus, we pay more attention to the TME in the pathogenesis of MM. Many researchers have identified that myeloma cells interact with the components of TME, which is beneficial for their survival, ultimately causing the formation of immunosuppressive and high-metabolism TME. In the process, transforming growth factor-β (TGF-β), as a pivotal cytokine in the TME, controls various cells' fates and influences numerous metabolic pathways, including inhibiting immune cells to infiltrate the tumors, suppressing the activation of anti-tumor immune cells, facilitating more immunosuppressive cells, enhancing glucose and glutamine metabolism, dysregulating bone metabolism and so on. Thus, we consider TGF-β as the tumor promoter. However, in healthy cells and the early stage of tumors, it functions as a tumor suppressor. Due to the effect of context dependence, TGF-β has dual roles in TME, which attracts us to further explore whether targeting it can overcome obstacles in the treatment of MM by regulating the progression of myeloma, molecular mechanisms of drug resistance, and various signaling pathways in the immune and metabolic microenvironment. In this review, we predominantly discuss that TGF-β promotes the development of MM by influencing immunity and metabolism.

SOHO State of the Art Updates and Next Questions: Diagnosis and Management of Monoclonal Gammopathy of Undetermined Significance and Smoldering Multiple Myeloma

Monoclonal proteins are common, with a prevalence in the United States around 5% and the incidence increases with age. Although most patients are asymptomatic, the vast majority of cases are caused by a clonal plasma cell disorder. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions with variable risk of progression to multiple myeloma (MM). In recent years, significant progress has been made to better understand the factors that lead to the development of symptoms and progression to myeloma. In this review, we summarize the current diagnosis treatment guidelines for MGUS and SMM and highlight recent advances that underscore a shifting paradigm in the evaluation and management of plasma cell precursor conditions.

Lymphomas with plasmablastic features: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology

Lymphomas with plasmablastic features are a heterogeneous group of aggressive and mostly uncommon neoplasms of varied aetiologies, presenting in immunocompetent individuals as well as in immunodeficiency, associated with EBV and Kaposi sarcoma virus infections, and some as progression from indolent B-cell lymphomas. They show overlapping diagnostic features and pose a differential diagnosis with other aggressive B-cell lymphomas that can downregulate the B-cell expression programme. The spectrum of rare reactive proliferations and all lymphomas defined by plasmablastic features, together with an expanding range of poorly characterised, uncommon conditions at the interface between reactive lymphoid proliferations and neoplasia submitted to the session V of the 20th European Association for Haematopathology/Society for Hematopathology lymphoma workshop are summarised and discussed in this paper.

Evaluation of an innovative new method for quantitation of plasma cells on CD138 immunohistochemistry

AIM

To compare the frequently used CD138 immunohistochemistry-based method of plasma cell quantitation, to a proposed new method, using interobserver and intraobserver concordance parameters.

METHODS

Archival CD138 immunohistochemically stained slides made from paraffin-embedded bone marrow biopsies of 33 patients with a confirmed diagnosis of multiple myeloma were used. Light microscopic examination was performed using low magnification lenses (10×) for both the overview estimation method (method A) and the new method (method B), and high magnification lenses (50×), for method B only. For method B, reviewers selected three areas with low, intermediate and high plasma cell densities using 10× lenses. Using a well-defined technique, the 50× lens was then used to count plasma cells as a percentage of all nucleated cells. After blinded relabelling of all the slides, the nine reviewers repeated the plasma cell quantitation using both methods. The plasma cell counts were obtained, and the review times were recorded.

RESULTS

Overall intraobserver concordance was comparable for method A (concordance correlation coefficient (CCC)=0.840) and method B (CCC=0.733). Interobserver concordance for method A (intraclass correlation coefficient (ICC)=0.793 and 0.713) and method B (ICC=0.657 and 0.658) indicated high similarity between reviewers. Method A showed poor interobserver concordance (ICC=0.105) at low plasma cell densities.

CONCLUSIONS

The new method is comparable to the frequently used overview estimation method in terms of intraobserver and interobserver concordance, and cost. The new method has superior interobserver concordance at low plasma cell densities. The new method appears more amenable to digital scanning and analysis.

Differences in the immunoglobulin gene repertoires of IgG versus IgA multiple myeloma allude to distinct immunopathogenetic trajectories

The analysis of the immunogenetic background of multiple myeloma (MM) has proven key to understanding disease ontogeny. However, limited information is available regarding the immunoglobulin (IG) gene repertoire in MM cases carrying different heavy chain isotypes. Here, we studied the IG gene repertoire in a series of 523 MM patients, of whom 165 and 358 belonged to the IgA and IgG MM groups, respectively. IGHV3 subgroup genes predominated in both groups. However, at the individual gene level, significant (p<0.05) differences were identified regarding IGHV3-21 (frequent in IgG MM) and IGHV5-51 (frequent in IgA MM). Moreover, biased pairings were identified between certain IGHV genes and IGHD genes in IgA versus IgG MM. Turning to the imprints of somatic hypermutation (SHM), the bulk of rearrangements (IgA: 90.9%, IgG: 87.4%) were heavily mutated [exhibiting an IGHV germline identity (GI) <95%]. SHM topology analysis disclosed distinct patterns in IgA MM versus IgG MM cases expressing B cell receptor IG encoded by the same IGHV gene: the most pronounced examples concerned the IGHV3-23, IGHV3-30 and IGHV3-9 genes. Furthermore, differential SHM targeting was also identified between IgA MM versus IgG MM, particularly in cases utilizing certain IGHV genes, alluding to functional selection. Altogether, our detailed immunogenetic evaluation in the largest to-date series of IgA and IgG MM patients reveals certain distinct features in the IGH gene repertoires and SHM. These findings suggest distinct immune trajectories for IgA versus IgG MM, further underlining the role of external drive in the natural history of MM.

High prevalence of Wilms tumor 1 expression in multiple myeloma and plasmacytoma: A cohort of 142 Asian patients' samples

Wilms tumor 1 (WT1) is a promising target antigen for cancer immunotherapy. However, WT1 protein expression and its clinical correlation in multiple myeloma (MM) patients are still limited. We, therefore, investigated WT1 expression in 142 bone marrow and plasmacytoma samples of MM patients at different stages of the disease by immunohistochemistry. The correlations between WT1 expression and clinical parameters or treatment outcomes were evaluated. The overall positive rate of WT1 expression was 91.5%; this high prevalence was found in both bone marrow and plasmacytoma samples, regardless of the disease status. Cytoplasmic WT1 expression was correlated with high serum free light chain ratio at presentation. However, no significant association between WT1 expression and treatment outcome was observed. This study confirms the high prevalence of WT1 expression in an Asian cohort of MM, encouraging the development of immunotherapy targeting WT1 in MM patients, particularly in those with extramedullary plasmacytoma or relapsed disease.

Myeloma Microenvironmental TIMP1 Induces the Invasive Phenotype in Fibroblasts to Modulate Disease Progression

Tissue inhibitors of metalloproteinases (TIMPs) are endogenous matrix metalloproteinase inhibitors. TIMP1 is produced by cancer cells and has pleiotropic activities. However, its role and source in multiple myeloma (MM) are unclear. Here, we evaluated TIMP1 protein and mRNA levels in bone marrow (BM) plasma cells and assessed the effects of TIMP1 expression on fibroblast invasive capacity using three-dimensional spheroid cell invasion assays. TIMP1 mRNA and protein levels were elevated when patients progressed from monoclonal gammopathy of undetermined significance or smouldering myeloma to MM. Furthermore, TIMP1 levels decreased at complete response and TIMP1 protein levels increased with higher international staging. TIMP1 mRNA levels were markedly higher in extramedullary plasmacytoma and MM with t(4;14). Overall survival and post-progression survival were significantly lower in MM patients with high TIMP1 protein. Recombinant TIMP1 did not directly affect MM cells but enhanced the invasive capacity of fibroblasts; this effect was suppressed by treatment with anti-TIMP1 antibodies. Fibroblasts supported myeloma cell invasion and expansion in extracellular matrix. Overall, these results suggested that MM-derived TIMP1 induces the invasive phenotype in fibroblasts and is involved in disease progression. Further studies are required to elucidate the specific roles of TIMP1 in MM and facilitate the development of novel therapies targeting the TIMP1 pathway.

Plasmablastic lymphoma: An update

Plasmablastic lymphoma (PBL) is a highly aggressive B cell non-Hodgkin lymphoma frequently associated with immunosuppression, particularly human immunodeficiency virus (HIV) infection. Although PBL is rare globally, South Africa has a high burden of HIV infection leading to a higher incidence of PBL in the region. Laboratory features in PBL may overlap with plasmablastic myeloma and other large B cell lymphomas with plasmablastic or immunoblastic morphology leading to diagnostic dilemmas. There are, however, pertinent distinguishing laboratory features in PBL such as a plasma cell immunophenotype with MYC overexpression, expression of Epstein-Barr virus-encoded small RNAs and lack of anaplastic lymphoma kinase (ALK) expression. This review aims to provide a summary of current knowledge in PBL, focusing on the epidemiology, pathophysiology, laboratory diagnosis and clinical management.

A personalized molecular approach in multiple myeloma: the possible use of RAF/RAS/MEK/ERK and BCL-2 inhibitors

Multiple myeloma (MM) is a blood cancer that derives from plasma cells (PCs), which will accumulate in the bone marrow (BM). Over time, several drugs have been developed to treat this disease that is still uncurable. The therapies used to treat the disease target immune activity, inhibit proteasome activity, and involve the use of monoclonal antibodies. However, MM is a highly heterogeneous disease, in fact, there are several mutations in signaling pathways that are particularly important for MM cell biology and that are possible therapeutic targets. Indeed, some studies suggest that MM is driven by mutations within the rat sarcoma virus (RAS) signaling cascade, which regulates cell survival and proliferation. The RAS/proto-oncogene, serine/threonine kinase (RAF)/mitogen-activated extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK signaling pathway is deregulated in several cancers, for which drugs have been developed to inhibit these pathways. In addition to the signaling pathways, the disease implements mechanisms to ensure the survival and consequently a high replicative capacity. This strategy consists in the deregulation of apoptosis. In particular, some cases of MM show overexpression of anti-apoptotic proteins belonging to the B cell lymphoma 2 (BCL-2) family that represent a possible druggable target. Venetoclax is an anti-BCL-2 molecule used in hematological malignancies that may be used in selected MM patients based on their molecular profile. We focused on the possible effects in MM of off-label drugs that are currently used for other cancers with the same molecular characteristics. Their use, combined with the current treatments, could be a good strategy against MM.

MiRNA as a Potential Target for Multiple Myeloma Therapy–Current Knowledge and Perspectives

Multiple myeloma (MM) is the second most common hematological malignancy. Despite the huge therapeutic progress thanks to the introduction of novel therapies, MM remains an incurable disease. Extensive research is currently ongoing to find new options. MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression at a post-transcriptional level. Aberrant expression of miRNAs in MM is common. Depending on their role in MM development, miRNAs have been reported as oncogenes and tumor suppressors. It was demonstrated that specific miRNA alterations using miRNA mimics or antagomirs can normalize the gene regulatory network and signaling pathways in the microenvironment and MM cells. These properties make miRNAs attractive targets in anti-myeloma therapy. However, only a few miRNA-based drugs have been entered into clinical trials. In this review, we discuss the role of the miRNAs in the pathogenesis of MM, their current status in preclinical/clinical trials, and the mechanisms by which miRNAs can theoretically achieve therapeutic benefit in MM treatment.

Defining genomic events involved in the evolutionary trajectories of myeloma and its precursor conditions

All patients with a diagnosis of multiple myeloma (MM) have a preceding, asymptomatic expansion of clonal plasma cells, clinically recognized as monoclonal gammopathy of undetermined significance or smoldering multiple myeloma (SMM). While most patients with monoclonal gammopathy of undetermined significance have a very small rate of progression, SMM is a widely heterogeneous condition where a fraction of patients will progress to symptomatic MM rather quickly, while others will experience an indolent clinical course. The differentiation between progressive and stable precursor condition thus represents one of the most important unmet clinical needs in the MM community. The ability to identify patients at high-risk of progression before major clonal expansion and onset of end-organ damage would enable strategies for early prevention and perhaps more effective intervention. All proposed criteria to predict the progression of myeloma precursor conditions are built around indirect markers of disease burden and, therefore, are generally able to accurately identify only a small fraction of patients in whom progression to MM is already occurring. Leveraging whole genome and exome sequencing, it has been shown that patients with stable myeloma precursor conditions are characterized by either absence or lower prevalence of distinct genomic events that are detectable in progressive precursor condition years before the progression. In this review, we discuss evolving genomic concepts and tools; and their ability to differentiate myeloma precursor conditions into two distinct entities: one benign (monoclonal gammopathy of benign significance) and another malignant (asymptomatic multiple myeloma).

Genome Instability in Multiple Myeloma: Facts and Factors

Multiple myeloma (MM) is a malignant neoplasm of terminally differentiated immunoglobulin-producing B lymphocytes called plasma cells. MM is the second most common hematologic malignancy, and it poses a heavy economic and social burden because it remains incurable and confers a profound disability to patients. Despite current progress in MM treatment, the disease invariably recurs, even after the transplantation of autologous hematopoietic stem cells (ASCT). Biological processes leading to a pathological myeloma clone and the mechanisms of further evolution of the disease are far from complete understanding. Genetically, MM is a complex disease that demonstrates a high level of heterogeneity. Myeloma genomes carry numerous genetic changes, including structural genome variations and chromosomal gains and losses, and these changes occur in combinations with point mutations affecting various cellular pathways, including genome maintenance. MM genome instability in its extreme is manifested in mutation kataegis and complex genomic rearrangements: chromothripsis, templated insertions, and chromoplexy. Chemotherapeutic agents used to treat MM add another level of complexity because many of them exacerbate genome instability. Genome abnormalities are driver events and deciphering their mechanisms will help understand the causes of MM and play a pivotal role in developing new therapies.

Dynamic monitoring of serum ferritin as an adverse prognostic biomarker in patients with multiple myeloma

Aim: Increased serum ferritin (SF) indicates an adverse prognosis in patients with hematologic malignancies. However, its prognostic significance in multiple myeloma (MM) remains unknown. Patients & methods: The impact of SF levels on outcomes in patients with MM was retrospectively analyzed and dynamically assessed. Results: At initial diagnosis, 188 out of 295 patients (63.7%) had high SF that correlated with poor prognosis factors including adverse overall survival and progression-free survival. SF expression was dynamically observed at different time points and SF levels significantly decreased after treatment induction. In addition, SF expression significantly increased at disease progression or relapse. Conclusion: SF can be used as a prognostic factor at initial diagnosis and relapse in patients with MM.

Disease heterogeneity, prognostication and the role of targeted therapy in multiple myeloma

Multiple myeloma (MM) is a clonal plasma cell malignancy with a heterogeneous disease course. Insights into the genetics of the disease have identified certain high-risk cytogenetic features that are associated with adverse outcomes. While the advances in therapy have translated into dramatic improvements in the outcome of patients with MM, those with high-risk genetic features continue to perform poorly. This has resulted in a need for clinical trials focusing on the high-risk subgroup of MM as they search for additional biomarkers and therapeutic targets continue. In this review, we discuss the currently existing data on prognostic and predictive biomarkers in MM and speculate the role of treatment stratification based on the genetic features of the disease.

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.

ERK phosphorylation is RAF independent in naïve and activated B cells but RAF dependent in plasma cell differentiation

Members of the RAF family of serine-threonine kinases are intermediates in the mitogen-activated protein kinase and extracellular signal-regulated kinase (MAPK-ERK) signaling pathway, which controls key differentiation processes in B cells. By analyzing mice with B cell-specific deletion of Raf1, Braf, or both, we showed that Raf-1 and B-Raf acted together in mediating the positive selection of pre-B and transitional B cells as well as in initiating plasma cell differentiation. However, genetic or chemical inactivation of RAFs led to increased ERK phosphorylation in mature B cells. ERK activation in the absence of Raf-1 and B-Raf was mediated by multiple RAF-independent pathways, with phosphoinositide 3-kinase (PI3K) playing an important role. Furthermore, we found that ERK phosphorylation strongly increased during the transition from activated B cells to pre-plasmablasts. This increase in ERK phosphorylation did not occur in B cells lacking both Raf-1 and B-Raf, which most likely explains the partial block of plasma cell differentiation in mice lacking both RAFs. Collectively, our data indicate that B-Raf and Raf-1 are not necessary to mediate ERK phosphorylation in naïve or activated B cells but are essential for mediating the marked increase in ERK phosphorylation during the transition from activated B cells to pre-plasmablasts.

Machine Learning Applicability for Classification of PAD/VCD Chemotherapy Response Using 53 Multiple Myeloma RNA Sequencing Profiles

Multiple myeloma (MM) affects ~500,000 people and results in ~100,000 deaths annually, being currently considered treatable but incurable. There are several MM chemotherapy treatment regimens, among which eleven include bortezomib, a proteasome-targeted drug. MM patients respond differently to bortezomib, and new prognostic biomarkers are needed to personalize treatments. However, there is a shortage of clinically annotated MM molecular data that could be used to establish novel molecular diagnostics. We report new RNA sequencing profiles for 53 MM patients annotated with responses on two similar chemotherapy regimens: bortezomib, doxorubicin, dexamethasone (PAD), and bortezomib, cyclophosphamide, dexamethasone (VCD), or with responses to their combinations. Fourteen patients received both PAD and VCD; six received only PAD, and 33 received only VCD. We compared profiles for the good and poor responders and found five genes commonly regulated here and in the previous datasets for other bortezomib regimens (all upregulated in the good responders): FGFR3, MAF, IGHA2, IGHV1-69, and GRB14. Four of these genes are linked with known immunoglobulin locus rearrangements. We then used five machine learning (ML) methods to build a classifier distinguishing good and poor responders for two cohorts: PAD + VCD (53 patients), and separately VCD (47 patients). We showed that the application of FloWPS dynamic data trimming was beneficial for all ML methods tested in both cohorts, and also in the previous MM bortezomib datasets. However, the ML models build for the different datasets did not allow cross-transferring, which can be due to different treatment regimens, experimental profiling methods, and MM heterogeneity.

SMARCA2 Is a Novel Interactor of NSD2 and Regulates Prometastatic PTP4A3 through Chromatin Remodeling in t(4;14) Multiple Myeloma

NSD2 is the primary oncogenic driver in t(4;14) multiple myeloma. Using SILAC-based mass spectrometry, we demonstrate a novel role of NSD2 in chromatin remodeling through its interaction with the SWI/SNF ATPase subunit SMARCA2. SMARCA2 was primarily expressed in t(4;14) myeloma cells, and its interaction with NSD2 was noncanonical and independent of the SWI/SNF complex. RNA sequencing identified PTP4A3 as a downstream target of NSD2 and mapped NSD2-SMARCA2 complex on PTP4A3 promoter. This led to a focal increase in the permissive H3K36me2 mark and transcriptional activation of PTP4A3. High levels of PTP4A3 maintained MYC expression and correlated with a 54-gene MYC signature in t(4;14) multiple myeloma. Importantly, this mechanism was druggable by targeting the bromodomain of SMARCA2 using the specific BET inhibitor PFI-3, leading to the displacement of NSD2 from PTP4A3 promoter and inhibiting t(4;14) myeloma cell viability. In vivo, treatment with PFI-3 reduced the growth of t(4;14) xenograft tumors. Together, our study reveals an interplay between histone-modifying enzymes and chromatin remodelers in the regulation of myeloma-specific genes that can be clinically intervened. SIGNIFICANCE: This study uncovers a novel, SWI/SNF-independent interaction between SMARCA2 and NSD2 that facilitates chromatin remodeling and transcriptional regulation of oncogenes in t(4;14) multiple myeloma, revealing a therapeutic vulnerability targetable by BET inhibition.

Double-Hit Primary Plasma Cell Leukemia with IGH/MYC and IGH/CCND1 Translocations

Primary plasma cell leukemia (pPCL) is an aggressive variant of multiple myeloma (MM). Immunoglobulin heavy chain (IgH) translocations are found in a majority of pPCL cases, supporting a central relation to pathogenesis of pPCL. However, two independent IgH translocations are barely detected at the onset of pPCL, and their significance is yet to be elucidated. Here, we report a case of an aggressive pPCL with simultaneous IGH/MYC and IGH/CCND1 translocations. A 73-year-old man was referred to our hospital with back pain and diagnosed as having pPCL with more than 50% circulating plasma cells. Cytogenetic analysis revealed 47, Y, t (X; 8;14) (q24; q24; q32), t (11; 14) (q13; q32), and +18. IGH/MYC and IGH/CCND1 translocations were confirmed by fluorescence in situ hybridization analysis. Bortezomib and dexamethasone treatment achieved rapid elimination of peripheral malignant plasma cells, and the patient maintained a partial response for 18 months. After biological relapse, he received salvage therapy with ixazomib, lenalidomide, and dexamethasone, followed by pomalidomide and dexamethasone, and exhibited stable disease for an additional 14 months. Although IGH/MYC translocation in association with dysregulation of antiapoptotic pathway leads to worse prognosis in lymphomas, the novel agent-based regimen showed good efficacy, suggesting that IGH/MYC plays a different role in the pathogenesis of MM. IGH/CCND1 and IGH/MYC translocations may have contributed to abrupt onset of pPCL in this case.

Diagnosis and Management of Monoclonal Gammopathy and Smoldering Multiple Myeloma

The presence of monoclonal proteins is common, with a prevalence in the United States around 5% that increases with age. Although most patients are asymptomatic, most cases are caused by a clonal plasma cell disorder. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions with variable risk of progression to multiple myeloma. In recent years, significant progress has been made to better understand the factors that lead to the development of symptoms and progression to myeloma. This review summarizes the current diagnosis treatment guidelines for MGUS and SMM and highlights recent advances that underscore a shifting paradigm in the evaluation and management of plasma cell precursor conditions.

Lenalidomide-Associated Secondary B-Lymphoblastic Leukemia/Lymphoma-A Unique Entity

OBJECTIVES

Autologous stem cell transplant with lenalidomide maintenance therapy has greatly improved the relapse-free and overall survival rates of patients with multiple myeloma but also has been associated with an increased risk of secondary B-lymphoblastic leukemia/lymphoma (B-ALL).

METHODS

We report a comprehensive review of the clinicopathologic features of 2 patients with multiple myeloma who developed secondary B-ALL during lenalidomide maintenance.

RESULTS

Our observations showed that the disease may initially present with subtle clinical, morphologic, and flow-cytometric findings. The flow cytometry findings in such cases may initially mimic an expansion of hematogones with minimal immunophenotypic variation. Both patients achieved complete remission of secondary B-ALL after standard chemotherapy; however, one patient continues to have minimal residual disease, and the other experienced relapse. Next-generation sequencing of the relapse specimen showed numerous, complex abnormalities, suggesting clonal evolution.

CONCLUSIONS

Our findings suggest the need for increased awareness and further study of this unique form of secondary B-ALL.

Prevalence of class I-III BRAF mutations among 114,662 cancer patients in a large genomic database

IMPACT STATEMENT

These data represent the largest aggregation of BRAF mutations within a single clinical database to our knowledge. The relative proportions of both BRAF V600 mutations and non-V600 mutations are informative in all cancers and by malignancy, and can serve as a definitive gold-standard for BRAF mutation cancer incidence by malignancy. The rate of BRAF mutation in human cancer in a real-world large database is lower than previously reported likely representing testing more broadly across tumor types. The relative percentages of Class II and Class III BRAF mutations are higher than previously reported, representing almost 35% of BRAF mutations in cancer. These findings provide support for the development of effective treatments for non-V600 BRAF mutations in cancer.

Long Noncoding RNA PVT1 Is Regulated by Bromodomain Protein BRD4 in Multiple Myeloma and Is Associated with Disease Progression

Long noncoding RNAs (lncRNAs) are deregulated in human cancers and are associated with disease progression. Plasmacytoma Variant Translocation 1 (PVT1), a lncRNA, is located adjacent to the gene MYC, which has been linked to multiple myeloma (MM). PVT1 is expressed in MM and is associated with carcinogenesis. However, its role and regulation remain uncertain. We examined PVT1/MYC expression using real-time PCR in plasma cells purified from 59 monoclonal gammopathy of undetermined significance (MGUS) and 140 MM patients. The MM cell lines KMS11, KMS12PE, OPM2, and RPMI8226 were treated with JQ1, an MYC super-enhancer inhibitor, or MYC inhibitor 10058-F4. The expression levels of PVT1 and MYC were significantly higher in MM than in MGUS (p < 0.0001) and were positively correlated with disease progression (r = 0.394, p < 0.0001). JQ1 inhibited cell proliferation and decreased the expression levels of MYC and PVT1. However, 10054-F4 did not alter the expression level of PVT1. The positive correlation between MYC and PVT1 in patients, the synchronous downregulation of MYC and PVT1 by JQ1, and the lack of effect of the MYC inhibitor on PVT1 expression suggest that the expression of these two genes is co-regulated by a super-enhancer. Cooperative effects between these two genes may contribute to MM pathogenesis and progression.

Targeting NF-κB Signaling for Multiple Myeloma

Multiple myeloma (MM) is the second most common hematologic malignancy in the world. Even though survival rates have significantly risen over the past years, MM remains incurable, and is also far from reaching the point of being managed as a chronic disease. This paper reviews the evolution of MM therapies, focusing on anti-MM drugs that target the molecular mechanisms of nuclear factor kappa B (NF-κB) signaling. We also provide our perspectives on contemporary research findings and insights for future drug development.

Genome instability in multiple myeloma

Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by clonal proliferation of plasma cells and a heterogenous genomic landscape. Copy number and structural changes due to chromosomal instability (CIN) are common features of MM. In this review, we describe how primary and secondary genetic events caused by CIN can contribute to increased instability across the genome of malignant plasma cells; with a focus on specific driver genomic events, and how they interfere with cell-cycle checkpoints, to prompt accelerated proliferation. We also provide insight into other forms of CIN, such as chromothripsis and chromoplexy. We evaluate how the tumor microenvironment can contribute to a further increase in chromosomal instability in myeloma cells. Lastly, we highlight the role of certain mutational signatures in leading to high mutation rate and genome instability in certain MM patients. We suggest that assessing CIN in MM and its precursors states may help improve predicting the risk of progression to symptomatic disease and relapse and identifying future therapeutic targets.

A multicenter retrospective study of 223 patients with t(14;16) in multiple myeloma

The t(14;16) translocation, found in 3%-5% of newly diagnosed (ND) multiple myeloma (MM), has been associated with adverse outcomes. However, the studies establishing the characteristics of t(14;16) included solely small cohorts. The goal of the current international, multicenter (n = 25 centers), retrospective study was to describe the characteristics and outcomes of t(14;16) patients in a large, real-world cohort (n = 223). A substantial fraction of patients had renal impairment (24%) and hemoglobin <10 g/dL (56%) on initial presentation. Combined therapy of both immunomodulatory drug and proteasome inhibitor (PI) in the first line was used in 35% of patients. Autologous stem cell transplantation was performed in 42% of patients. With a median follow up of 4.1 years (95% CI 3.7-18.7), the median progression-free survival (PFS) and overall survival (OS) from first line therapy were 2.1 years (95% CI 1.5-2.4) and 4.1 years (95% CI 3.3-5.5), respectively. Worse OS was predicted by age > 60 years (HR = 1.65, 95% CI [1.05-2.58]), as well as revised International Scoring System (R-ISS) 3 (vs R-ISS 2; HR = 2.59, 95% CI [1.59-4.24]). In conclusion, based on the largest reported cohort of t(14;16) patients, quarter of this subset of MM patients initially presents with renal failure, while older age and the R-ISS 3 predict poor survival.

Plasma Cell Fate Is Orchestrated by Elaborate Changes in Genome Compartmentalization and Inter-chromosomal Hubs

The transition from the follicular B to the plasma cell stage is associated with large-scale changes in cell morphology. Here, we examine whether plasma cell development is also associated with changes in nuclear architecture. We find that the onset of plasma cell development is concomitant with a decline in remote genomic interactions; a gain in euchromatic character at loci encoding for factors that specify plasma cell fate, including Prdm1 and Atf4; and establishment of de novo inter-chromosomal hubs. We find that, in developing plasma cells and concurrent with transcriptional silencing, the Ebf1 locus repositions from an euchromatic to peri-centromeric heterochromatic environment. Finally, we find that inter-chromosomal hubs are enriched for the deposition of either H3K27Ac or H3K27me3. These data indicate that plasma cell fate is orchestrated by elaborate changes in genome topology and that epigenetic marks, linked with super-enhancers or transcriptionally repressed regions, are enriched at inter-chromosomal hubs.

Maximizing the Clinical Benefit of Radiotherapy in Solitary Plasmacytoma: An International Multicenter Analysis

Objective: Although local definitive radiotherapy (RT) is considered the standard of care for solitary plasmacytoma (SP), the optimal RT parameters for SP patients have not been defined. The aim of this retrospective study is to analyze the effectiveness of various RT doses, volumes, and techniques, as well as to define the relevant prognostic factors in SP. Methods: Between 2000 and 2019, 84 patients, including 54 with solitary bone plasmacytoma (SBP) and 30 with extramedullary plasmacytoma (EMP), underwent RT at six institutions. Results: The overall RT median dose was 42 Gy (range, 36.0–59.4). The median follow-up period was 46 months. Overall, the local control (LC) rate was 96%, while the complete remission (CR) rate was 46%. The 5-year local relapse-free survival (LRFS), multiple myeloma-free survival (MMFS), progression-free survival (PFS), and overall survival (OS) rates were 89%, 71%, 55%, and 93%, respectively. Using an RT dose above 40 Gy was associated with a higher complete remission (CR) rate and a lower rate of local relapse. Modern irradiation techniques were associated with a trend toward a higher LC rate (98% vs. 87% for conventional, p = 0.09) and a significantly lower local relapse rate (6% vs. 25% for conventional, p = 0.04). However, RT dose escalation and technique did not lead to a significant effect on MMFS, PFS, and OS. Univariate analyses identified several patient characteristics as potentially relevant prognostic factors. In SBP patients, systemic therapy administration was associated significantly with MMFS and PFS rates. Conclusion: Using an RT dose >40 Gy and modern RT techniques may improve the local control and reduce the rate of relapse, without a significant impact on survival rates. The addition of systemic therapies may improve the MMFS and PFS rates of SBP patients.

Lymphoid Neoplasms With Plasmablastic Differentiation: A Comprehensive Review and Diagnostic Approaches

Plasmablastic neoplasms encompass several entities including plasmablastic lymphoma, plasmablastic plasmacytoma/multiple myeloma, primary effusion lymphoma and its extracavitary variant, anaplastic lymphoma kinase-positive large B-cell lymphoma, and Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 (HHV8)-positive diffuse large B-cell lymphoma, not otherwise specified. Morphologically, the tumor cells are large with eccentrically located nuclei, prominent nucleoli, and basophilic/amphophilic cytoplasm. Immunophenotypically, the tumor cells express plasma cell-related antigens including CD38, CD138, interferon regulatory factor-4 (IRF4)/MUM1, PR domain zinc finger protein-1 (PRDM1), and/or X-box binding protein-1 (XBP1), with frequent loss of CD20. These tumors are diagnostically challenging for general pathologists due to their overlapping morphology and immunophenotype, and due to their rarity, and particularly so when clinical and radiologic information is insufficient. We also discuss HHV8-negative effusion-based lymphoma due to its overlapping features with primary effusion lymphoma. In this review, we focus on the useful diagnostic markers and pertinent molecular findings in these distinct entities and propose a practical diagnostic algorithm using anaplastic lymphoma kinase, HHV8, in situ hybridization for Epstein-Barr virus-encoded small RNA, immunoglobulin M, light chain stains, and clinicoradiologic criteria to avoid misdiagnosis. At the molecular level, MYC protein overexpression with or without MYC rearrangement and PRDM1-inactivating mutations or deletions are noted in a subset of such tumors, especially in plasmablastic lymphoma. Prognosis in these entities is dismal with conventional CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy. Therefore, novel target therapies, such as anti-CD30 agents, and/or immune blockade therapy, are potential treatment options in the future.

Receipt of Statins Is Associated With Lower Risk of Multiple Myeloma: Systematic Review and Meta-analysis

BACKGROUND

Studies on receipt of statins and risk of multiple myeloma (MM) yielded conflicting results. This systematic review and meta-analysis was conducted in order to comprehensively investigate the relationship between receipt of statins and risk of MM.

PATIENTS AND METHODS

Potentially eligible studies that compared the risk of MM between statin recipients and those who did not receive statins were identified from Medline and Embase databases from inception to August 2019 using a search strategy that comprised terms for "statin" and "multiple myeloma." To be eligible, cohort studies must have recruited 2 groups of participants, statin recipients and nonrecipients, and followed their participants for incident MM. Eligible case-control studies must have recruited cases of MM and controls without MM, and must have explored the history of receipt of statins. Relative risk, hazard risk ratio, standardized incidence ratio, or odds ratio (OR) of this association must be reported. Relative risk and standard error from each study were extracted and combined using random-effect generic inverse variance. Relative risk of cohort study was used as an estimate for OR to calculate the pooled effect estimate along with the OR of the case-control studies.

RESULTS

A total of 1744 articles were identified using the search strategy, and 10 studies were included in the meta-analysis. The odds of MM were significantly lower among statin recipients than nonrecipients, with a pooled OR of 0.80 (95% confidence interval, 0.68-0.93; I² 72%). The funnel plot was relatively symmetrical and did not suggest publication bias.

CONCLUSION

Receipt of statins is associated with a significant 20% reduction in the odds of MM.

Overcoming Proteasome Inhibitor-Refractory Multiple Myeloma With Elotuzumab, Bortezomib, Nelfinavir, and Dexamethasone

Multiple myeloma is a common plasma cell malignancy with a median overall survival of fewer than 10 years. Proteasome inhibitors comprise an important part of the treatment regimen for this disease. The present study reports the case of a 57-year-old man who experienced a second relapse of multiple myeloma 6 years after initial treatment with bortezomib, lenalidomide, dexamethasone (VRD) followed by autologous hematopoietic cell transplant. The first relapse had been successfully treated with VRD, but this approach failed to control his second relapse. Given the lack of response to VRD therapy and relapse while on bortezomib maintenance, the patient was deemed proteasome inhibitor-refractory and received a new treatment of elotuzumab, lenalidomide, and dexamethasone. Four and a half cycles were completed before the treatment was stopped due to grade 4 cytopenias. The patient received a novel combination of elotuzumab, bortezomib, nelfinavir, and dexamethasone. After six cycles, the serum M-protein level was improved to 0.6 g/dL and the kappa light chains dropped from 3.49 to 1.04 mg/dL. A bone marrow biopsy conducted after five treatment cycles demonstrated < 1% plasma cells by immunohistochemistry and achievement of minimal residual disease status. Overall, this case study suggests that proteasome inhibitor-refractory multiple myeloma may be successfully re-treated with proteasome inhibitors when co-administered with nelfinavir.

Gm6377 suppressed SP 2/0 xenograft tumor by down-regulating Myc transcription

PURPOSE

Disturbed process of B-cell differentiation into plasmablasts (PBs)/plasma cells (PCs) is involved in multiple myeloma (MM). New strategies will be required to eliminate the MM cell clone for a long-term disease control. Because of its PB-like characteristics, the mus musculus myeloma SP 2/0 cell line was used in this study to search novel targets for PBs/PCs.

METHODS/PATIENTS

Affymetrix microarrays and RNA-sequencing assays were used to search a novel different molecule (Gm6377) between PBs/PCs and mature B cells. Cell counting kit-8 (CCK8), flow cytometry (FACS), xenograft mouse model, and the luciferase reporter system were used to assess the effect of Gm6377 on SP 2/0 cell proliferation, cell cycle, tumor growth, and Myc promoter activation, respectively.

RESULTS

We found that B cells expressed a high level of Gm6377 mRNA, whereas Gm6377 mRNA was decreased in PCs. In addition, SP 2/0 cells also expressed low levels of Gm6377 mRNA. Critically, Gm6377 overexpression suppressed SP 2/0 cell proliferation but not cell cycle. Furthermore, Gm6377 overexpression suppressed tumor progression in the SP 2/0 xenograft mouse model. Finally, we found that Gm6377 suppressed SP 2/0 cell proliferation by reducing the activation of the Myc promoter.

CONCLUSIONS

These results suggest that Gm6377 suppresses myeloma SP 2/0 cell growth by suppressing Myc. Thus, modulation of Gm6377 may be a potential therapeutic way to treat MM.

New generation drugs for treatment of multiple myeloma

Multiple myeloma (MM), a plasma cell malignancy, is characterised by lesions in multiple bones involving transformed, matured post-follicular B cells. The course of the disease involves an initial development of monoclonal gammopathy of undetermined significance (MGUS), followed by smouldering MM, before the full MM disease emerges. Despite novel therapies, MM remains incurable, managed by combination therapies, including proteasome inhibitors (PIs), immunomodulators (IMiDs) and anti-human CD38 (daratumumab). MM patients have an increased risk of thromboembolic events due to combination treatments with IMiDs, PIs and anti-human CD38 antibody, and steroids. This review will examine the efficacy and pro-thrombotic effects of MM therapies.

Immunohistochemistry for identification of CCND1, NSD2, and MAF gene rearrangements in plasma cell myeloma

The t(11;14)/CCND1‐IGH, t(4;14)/NSD2(MMSET)‐IGH, and t(14;16)/IGH‐MAF gene rearrangements detected by fluorescence in situ hybridization (FISH) are used for risk stratification in patients with multiple myeloma (MM). Compared with conventional FISH techniques using fresh cells, immunohistochemistry (IHC) is much more cost‐ and time‐efficient, and can be readily applied to routinely prepared formalin‐fixed, paraffin‐embedded (FFPE) materials. In this study, we performed tissue FISH and IHC employing FFPE specimens, and examined the usefulness of IHC as a tool for detecting CCND1,NSD2, and MAF gene rearrangements. CD138 signals were used to identify plasma cells in tissue FISH and IHC analyses. With cohort 1 (n = 70), we performed tissue FISH and subsequently IHC, and determined IHC cut‐off points. In this cohort, the sensitivity and specificity for the 3 molecules were ≥.90 and ≥.96, respectively. With cohort 2, using MM cases with an unknown gene status (n = 120), we performed IHC, and the gene status was estimated using the cut‐off points determined with cohort 1. The subsequent FISH analysis showed that the sensitivity and specificity for the 3 molecules were ≥.92 and ≥.98, respectively. CCND1, NSD2, and MAF gene rearrangements were estimated accurately by IHC, suggesting that conventional FISH assays can be replaced by IHC.

Impact of chromosomal abnormalities on the efficacy of lenalidomide plus dexamethasone treatment in patients with relapsed/refractory multiple myeloma

Lenalidomide is an effective therapeutic agent for multiple myeloma (MM). However, its efficacy in the context of chromosomal abnormalities (CA) is poorly understood. We retrospectively analyzed 83 patients with relapsed/refractory (RR) MM, who received lenalidomide plus low-dose dexamethasone (Ld), in the context of CA. The median age and number of prior therapies were 69 and 2, respectively. Three, 11, 45, and 19 patients achieved complete response, very good partial response, partial response, and stable disease, respectively. Median progression-free survival (PFS) and overall survival (OS) were 11.1 and 38.8 months, respectively. Seventy-two patients were evaluated for frequently observed translocations; median PFS was 24.4 months in 20 patients with t(11;14), 13.0 months in 16 patients with t(4;14), and 3.7 months in seven patients with t(14;16). G-banded karyotype analysis detected 11 hypodiploid patients, who had shorter PFS and OS (2.5 and 6.2 months, respectively) compared to others (13.0 and 43.7 months, respectively). Hypodiploid patients showed poor clinical outcome, whereas patients with t(11;14) showed favorable outcome. In summary, the present study presents the clinical impact of chromosomal abnormalities on the outcome of Ld therapy, and contributes to understanding the appropriate choice of lenalidomide-based therapy to achieve effective treatment of RR MM.

Endogenous APOBEC3B Overexpression Constitutively Generates DNA Substitutions and Deletions in Myeloma Cells

Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like (APOBEC) DNA cytosine deaminases have emerged as potential genomic mutators in various cancers. Multiple myeloma accumulates APOBEC signature mutations as it progresses; however, the mechanisms underlying APOBEC signature acquisition and its consequences remain elusive. In this study, we examined the significance and clinical impact of APOBEC3B (A3B) activity in multiple myeloma. Among APOBECs, only highly expressed A3B was associated with poor prognosis in myeloma patients, independent of other known poor prognostic factors. Quantitative PCR revealed that CD138-positive primary myeloma cells and myeloma cell lines exhibited remarkably high A3B expression levels. Interestingly, lentiviral A3B knockdown prevented the generation of deletion and loss-of-function mutations in exogenous DNA, whereas in control cells, these mutations accumulated with time. A3B knockdown also decreased the basal levels of γ-H2AX foci, suggesting that A3B promotes constitutive DNA double-strand breaks in myeloma cells. Importantly, among control shRNA-transduced cells, we observed the generation of clones that harboured diverse mutations in exogenous genes and several endogenous genes frequently mutated in myeloma, including TP53. Taken together, the results suggest that A3B constitutively mutates the tumour genome beyond the protection of the DNA repair system, which may lead to clonal evolution and genomic instability in myeloma.

Impact of radiation dose on local control and survival in extramedullary head and neck plasmacytoma

Background

Patients with plasma-cell neoplasia usually suffer from systemic disease, although a minority (< 5%) may present with solitary involvement of bone or soft tissue (extramedullary plasmacytoma (EMP)). Radiotherapy (RT) is a state-of-the-art treatment for these tumors offering long term curation.

Methods and materials

Between January 2005 and January 2017, twenty-seven patients underwent RT at our institution. The aim of this study was to analyse the effectiveness of various RT doses for different forms of EMP.

Results

A total of 33 radiation courses were administered to 27 patients with a median age of 56 years. The median RT dose was 45 Gy (range: 12–55.8). The local control rate was 76% (93% for primary EMP vs. 61% for the secondary EMP lesions; P < 0.05). A complete response (CR) rate to local RT was achieved for 42% lesions (67% for primary EMP vs. 22% for the secondary EMP lesions; P < 0.01). The overall response rate (ORR) for the EMP lesions treated with high-dose regimens (> 45 Gy) versus low-dose regimens (≤ 45 Gy) was 87% versus 67%, respectively (P = 0.2). The median survival with high-dose RT group was significantly longer (P = 0.02). In subgroups analysis, primary EMP patients treated with high-dose RT had a non-significant higher ORR (100% vs. 80%, respectively; P = 0.3,) longer duration of LC (P = 0.3) with a longer survival (P = 0.05) than patients in low-dose group. No significant difference has been detected in secondary EMP patients treated with high-dose RT regarding ORR (60% vs. 62%, respectively; P = 1), and survival (P = 0.4).

Conclusion

RT is an efficacious treatment modality in the treatment of EMP. A radiation dose ≤45 Gy confer a comparable CR rate to high-dose regimens and appears to be an effective treatment for controlling local EMP progression. Radiation dose-escalation may be beneficial for particular subgroups of patients.

Light-chain plasma cell myeloma caused by 14q32/IGH translocation and loss of the other allele

Light-chain plasma cell myeloma (LC-PCM) is a PCM subtype in which only immunoglobulin light-chain is secreted. However, the absence of immunoglobulin heavy-chain (IGH) production in this condition has not been fully elucidated. To address this issue, we retrospectively analyzed patients at our center with LC-PCM and found a group who had only split signals of IGH gene derived from 14q32/IGH translocations by fluorescence in situ hybridization (FISH). Six patients were identified with only split signals of the IGH gene derived from 14q32/IGH translocations. Five of these patients were newly diagnosed, while one had IgG-λ PCM at presentation, which transformed to λ LC-PCM after treatment. The translocation partners were identified in four patients: two cases of (11;14)(q13;q32) and two cases of (4;14)(p16;q32). The development of LC-PCM appears to be explained by the application of allelic exclusion in these patients, such that 14q32/IGH translocation in one allele contributes to the pathogenesis of PCM and the subsequent loss of the other allele is responsible for the loss of IGH production. These findings suggest that a FISH pattern of IGH with "split and loss" may constitute a unique subgroup of LC-PCM.

Flow Cytometric Evaluation of Traditional and Novel Surface Markers for the Diagnosis of Plasma Cell Dyscrasias

Increasing interest has been expressed for flow cytometric immunophenotyping for diagnosis and monitoring in plasma cell dyscrasias over the last decades. The aim of this investigation was to compare the expression strength of various cell surface markers used traditionally or currently under investigation on normal and abnormal PC populations. We enrolled 295 consecutive patients undergoing bone marrow aspiration in the workup of monoclonal gammopathies, selecting 54 normal and 241 abnormal PC populations via flow cytometry to characterize the expression of CD45, CD38, CD138, CD19, CD56, CD20, CD27, CD28, CD81, CD117 and CD200 on the cell surface of PCs. We observed significant differences in the expression strength of all assessed markers between normal and abnormal PC populations in all markers except for CD20. While none of them was conclusive on its own, the combination of CD81 positivity and CD117 negativity was present in 98.1% of normal PC populations tested. In contrast, particularly CD117 positivity, but also CD81 negativity was indicative of an abnormal PC phenotype. Our results highlight the descriptive value of CD81 and CD117 for the allocation of bone marrow PCs to a normal or abnormal phenotype.

Newly diagnosed multiple myeloma patients carrying monoallelic deletion of the whole locus of immunoglobulin heavy chain gene have a better prognosis compared to those with t(4;14) and t(14;16)

The current study evaluated the prognostic significance of the monoallelic deletion of the whole locus of the immunoglobulin heavy-chain (w_del(IGH)) gene compared to translocations t(4;14) and t(14;16) among newly diagnosed multiple myeloma (MM) patients. We retrospectively analyzed clinical (age, gender, and staging) and laboratory data at diagnosis and the overall survival (OS) of 255 newly diagnosed MM patients carrying w_del(IGH) or translocations t(4;14) or t(14;16). Bone marrow samples were examined by morphological and sequential interphase fluorescense in situ hybridization analyses. Among 255 patients, 117 (45.8%) had w_del(IGH), 99 (38.8%) had t(4;14), and 39 (15.3%) had t(14;16). Mean age was 61.6 ± 11.6 years. Groups did not differ significantly in age, gender, or lactate dehydrogenase levels. Patients in the w_del(IGH) group presented more frequently at International Staging System stage I than at stage II/III. Patients in the w_del(IGH) group had significantly fewer additional chromosomal aberrations (1.58) than the other two groups (2.3 and 2.13 in the del(IGH), t(14;16) and t(4;14) groups, respectively, P < 0.0001). Furthermore, the w_del(IGH) group had significantly longer estimated median OS (9.47 years) compared to those with translocations t(14;16) (3.02 years, P = 0.002) or t(4;14) (4.18 years, P = 0.001), respectively. These findings suggest a potential prognostic significance of monoallelic deletion of IGH among these patients. Additional studies are needed to better understand the nature and mechanism of this prognostic factor.

HIF-2α-ILK Is Involved in Mesenchymal Stromal Cell Angiogenesis in Multiple Myeloma Under Hypoxic Conditions

Mesenchymal stromal cells are proven to be likely induce the angiogenic response in multiple myeloma and thus represent an enticing target for antiangiogenesis therapies for multiple myeloma. Substantial evidence indicates that angiogenesis in multiple myeloma is complex and involves direct production of angiogenic cytokines by abnormal plasma cells and these B-cell neoplasia generated pathophysiology change within the microenvironment. In this study, we demonstrated that mesenchymal stromal cells cultured with U266/Lp-1 under hypoxic conditions resulted in an increased α-smooth muscle actin expression and high productive levels of both hypoxia-inducible factor-2α and integrin-linked kinase proteins. Moreover, inhibition of hypoxia-inducible factor-2α by Small interfering RNA (siRNA) in mesenchymal stromal cells decreased the protein levels of both α-smooth muscle actin and integrin-linked kinase after mesenchymal stromal cells cultured with U266 under hypoxic conditions. We further demonstrated that transfection of integrin-linked kinase-siRNA reduced the protein level of α-smooth muscle actin and attenuated angiogenesis in vitro by decreasing the attachment of Q-dot labeled cells and secretion of angiogenic factors. In conclusion, our research showed that mesenchymal stromal cells cultured with myeloma cells under hypoxia participated in the angiogenesis of multiple myeloma, which is regulated by the hypoxia-inducible factor-2α-integrin-linked kinase pathway. Thus, targeting integrin-linked kinase may represent an effective strategy to block hypoxia-inducible factor-2α-induced angiogenesis in the treatment of multiple myeloma.

Technical Advances in Single-Cell RNA Sequencing and Applications in Normal and Malignant Hematopoiesis

Single-cell RNA sequencing (scRNA-seq) has been tremendously developed in the past decade owing to overcoming challenges associated with isolation of massive quantities of single cells. Previously, cell heterogeneity and low quantities of available biological material posed significant difficulties to scRNA-seq. Cell-to-cell variation and heterogeneity are fundamental and intrinsic characteristics of normal and malignant hematopoietic cells; this heterogeneity has often been ignored in omics studies. The application of scRNA-seq has profoundly changed our comprehension of many biological phenomena, including organ development and carcinogenesis. Hematopoiesis, is actually a maturation process for more than ten distinct blood and immune cells, and is thought to be critically involved in hematological homeostasis and in sustaining the physiological functions. However, aberrant hematopoiesis directly leads to hematological malignancy, and a deeper understanding of malignant hematopoiesis will provide deeper insights into diagnosis and prognosis for patients with hematological malignancies. Here, we aim to review the recent technical progress and future prospects for scRNA-seq, as applied in physiological and malignant hematopoiesis, in efforts to further understand the hematopoietic hierarchy and to illuminate personalized therapy and precision medicine approaches used in the clinical treatment of hematological malignancies.

Plasma cell myeloma with dual expression of kappa and lambda light chains

Plasma cell myeloma is a clonal proliferation of neoplastic plasma cells and typically expresses a monoclonal heavy and/or light chain immunoglobulin. Plasma cell myeloma with dual expression of kappa and lambda light chains in a single clone is extremely rare. Here we report three cases of plasma cell myeloma with a co-expression of both kappa and lambda light chains. All three cases were confirmed by comprehensive workup including IHC, ISH and flow cytometry analysis to detect light chain expression patterns at the mRNA and protein levels. We also reviewed three cases so far published in the literature. Our study suggests that plasma cell myeloma with dual light chain expression may be more likely to be light chain only myeloma. It may have a high frequency of complex cytogenetic and/or FISH abnormalities, associated with a high-risk disease.

Prognostic impact of hyperdiploidy in multiple myeloma patients with high-risk cytogenetics: a pilot study in China

PURPOSE

Multiple myeloma is genetically heterogeneous with varied clinical outcomes, primarily due to the coexistence of diverse numerical and structural cytogenetic abnormalities. The prognostic impact of hyperdiploidy in myeloma patients with high-risk cytogenetics remains controversial in Western studies and is unknown in China.

METHODS

We examined the cytogenetic features of hyperdiploidy in 201 Chinese patients with newly diagnosed myeloma using magnetic-activated cell sorting and interphase fluorescence in situ hybridization and analyzed the effect of hyperdiploidy on the prognosis of patients with high-risk cytogenetics.

RESULTS

Hyperdiploidy was detected in 50.7% (102/201) of the examined patients, and the incidence of hyperdiploidy coexisting with high-risk cytogenetics [del(17p13), +1q21 and adverse t(14q32)] was 33.8% (68/201). Survival analysis showed that the median progression-free survival (PFS) and 2-year overall survival (OS) of patients were better for hyperdiploidy than those for non-hyperdiploidy (43 vs. 20 months, P = 0.01; 86.8% vs. 70.5%, P = 0.04) and for standard-risk cytogenetics than those for high-risk cytogenetics (not reached vs. 23 months, P = 0.0001; 87.6% vs. 74.4%, P = 0.01). Strikingly, the high-risk cytogenetics patients with hyperdiploidy showed a better median PFS than those without hyperdiploidy (34 vs. 15 months, P = 0.01); however, compared to standard-risk cytogenetics patients, the median PFS and 2-year OS were poorer (34 months vs. not reached, P = 0.02; 78.8% vs. 87.6%, P = 0.05). The independent predictors of PFS were non-hyperdiploidy, high-risk cytogenetics, and bone marrow plasma cells ≥ 30%, with hazard ratios of 2.01 (95% CI 1.25-3.25), 2.56 (95% CI 1.38-4.74), and 1.81 (95% CI 1.08-3.05), respectively, and those for OS were non-hyperdiploidy and serum lactate dehydrogenase ≥ 250 U/L, with hazard ratios of 2.53 (95% CI 1.24-5.46) and 3.53 (95% CI 1.50-6.96), respectively.

CONCLUSIONS

These results suggest that the coexistence of hyperdiploidy may ameliorate the adverse prognosis of multiple myeloma patients with high-risk cytogenetics. High-risk cytogenetics patients without hyperdiploidy showed the worst prognosis.

The histopathology of myeloma in the bone marrow

Myeloma is characterized by the neoplastic proliferation of monoclonal plasma cells. A diagnosis of myeloma is based on the criteria proposed by the International Myeloma Working Group and the pathological findings.Myeloma cells are classified into four types: mature, immature, pleomorphic, and plasmablastic. There are three patterns in which myeloma infiltrates bone marrow - nodular, interstitial, and diffuse. Dutcher bodies are highly specific to neoplastic myeloma cells. On immunohistochemical staining, the specificity of CD138 is high for plasma cells. As a clear image is often not obtained from the immunohistochemical staining of the immunoglobulin light chain, in situ hybridization is recommended. Abnormal expression of CD56 is seen in 70-80% of cases by flow cytometry analysis. CD56 expression definitively indicates myeloma, suggesting its high diagnostic value. Evaluation of the infiltration pattern, monoclonality, and abnormal antigen expression of plasma cells is more important than the plasmocytic ratio to determine whether a case is reactive or neoplastic.Multiple gene abnormalities function in the onset and progression of myeloma. In our department, we analyze CCND1, FGFR3, MAF, and del (17p13) by FISH for all myeloma cases. None of the cases with genetic abnormalities were recognized by G-banding. Therefore, FISH is more effective than G-banding for the evaluation of genetic abnormalities in myeloma.

Myc protein overexpression is a feature of progression and adverse prognosis in multiple myeloma

OBJECTIVE

Prognostic and predictive markers in multiple myeloma are continuously explored because of the heterogeneity of the tumor biology. Myc protein is the final product from activating MYC oncogene, but the prognostic impact in multiple myeloma is not well described.

METHODS

In a population-based cohort of 194 untreated, newly diagnosed patients with multiple myeloma, we assessed myc protein expression using CD138/myc immunohistochemical double stain and collected clinicopathological data.

RESULTS

Cases with myc protein expression ≥40% (mycHIGH ) had a median overall survival of 11 months compared to 48 months in cases of myc protein expression <40% (mycLOW ) (P < 0.01). MycHIGH was significantly correlated to R-ISS, high proliferation index, high percentage of plasma cell in bone marrow, plasmablastic morphology, high calcium level, and abnormal karyotype. In multivariate survival analyses, mycHIGH was independently associated with inferior overall survival with a hazard ratio of 2.5.

CONCLUSION

Our results indicate myc protein overexpression to be associated with advanced multiple myeloma and poor prognosis.