Inherited genetic susceptibility to multiple myeloma

Prevalence and impact of diabetes on survival of patients with multiple myeloma in different racial groups

ABSTRACT

Multiple myeloma (MM) is twice as common in Black individuals compared with in White individuals, and diabetes mellitus (DM) disproportionately affects Black patients. Although numerous studies have shown a correlation between DM and MM, this has not been studied in the context of race and in vivo mechanisms. We conducted a retrospective clinical study of 5383 patients with MM of which 15% had DM (White, 12% and Black, 25%). Multivariable Cox models showed reduced overall survival (OS) for patients with DM (hazard ratio, 1.27; 95% confidence interval, 1.11-1.47; P < .001). This appeared to be driven by a marked difference in OS between White patients with and without DM but not in Black patients. In contrast, obesity was associated with better OS in Black patients but not in White patients. To complement this analysis, we assessed MM growth in a genetically engineered immunocompromised nonobese diabetic (Rag1-/-/muscle creatinine kinase promoter expression of a human IGF1R [M] with a lysine [K] to arginine [R] point mutation) mouse model to evaluate the mechanisms linking DM and MM. MM.1S xenografts grew in more Rag1-/-/MKR mice and grew more rapidly in the Rag1-/-/MKR mice compared with in controls. Western blot analysis found that MM1.S xenografts from Rag1-/-/MKR mice had higher phosphorylated S6 ribosomal protein (Ser235/236) levels, indicating greater activation of the mammalian target of rapamycin pathway. Our study is, to our knowledge, the first to evaluate racial differences in DM prevalence and survival in MM, as well as the effect of DM on tumor growth in mouse models. Our results suggest that DM may contribute to the higher incidence of MM in Black patients; and to improve survival in MM, DM management cannot be ignored.

Clinical characteristics and outcome of 318 families with familial monoclonal gammopathy: A multicenter Intergroupe Francophone du Myélome study

Familial forms of monoclonal gammopathy, defined as multiple myeloma (MM) or Monoclonal Gammopathy of Undetermined Significance (MGUS), are relatively infrequent and most series reported in the literature describe a limited number of families. MM rarely occurs in a familial context. MGUS is observed much more commonly, which can in some cases evolve toward full-blown MM. Although recurrent cytogenetic abnormalities have been described in tumor cells of sporadic cases of MM, the pathogenesis of familial MM remains largely unexplained. In order to identify genetic factors predisposing to familial monoclonal gammopathy, the Intergroupe Francophone du Myélome identified 318 families with at least two confirmed cases of monoclonal gammopathy. There were 169 families with parent/child pairs and 164 families with cases in at least two siblings, compatible with an autosomal transmission. These familial cases were compared with sporadic cases who were matched for age at diagnosis, sex and immunoglobulin isotype, with 10 sporadic cases for each familial case. The gender distribution, age and immunoglobulin subtypes of familial cases were unremarkable in comparison to sporadic cases. With a median follow-up of 7.4 years after diagnosis, the percentage of MGUS cases having evolved to MM was 3%. The median overall survival of the 148 familial MM cases was longer than that of matched sporadic cases, with projected values of 7.6 and 16.1 years in patients older and younger than 65 years, respectively. These data suggest that familial cases of monoclonal gammopathy are similar to sporadic cases in terms of clinical presentation and carry a better prognosis.

Myeloma immunoglobulin rearrangement and translocation detection through targeted capture sequencing

Multiple myeloma is a plasma cell neoplasm characterized by clonal immunoglobulin V(D)J signatures and oncogenic immunoglobulin gene translocations. Additional subclonal genomic changes are acquired with myeloma progression and therapeutic selection. PCR-based methods to detect V(D)J rearrangements can have biases introduced by highly multiplexed reactions and primers undermined by somatic hypermutation, and are not readily extended to include mutation detection. Here, we report a hybrid-capture approach (CapIG-seq) targeting the 3' and 5' ends of the V and J segments of all immunoglobulin loci that enable the efficient detection of V(D)J rearrangements. We also included baits for oncogenic translocations and mutation detection. We demonstrate complete concordance with matched whole-genome sequencing and/or PCR clonotyping of 24 cell lines and report the clonal sequences for 41 uncharacterized cell lines. We also demonstrate the application to patient specimens, including 29 bone marrow and 39 cell-free DNA samples. CapIG-seq shows concordance between bone marrow and cfDNA blood samples (both contemporaneous and follow-up) with regard to the somatic variant, V(D)J, and translocation detection. CapIG-seq is a novel, efficient approach to examining genomic alterations in myeloma.

Family history of plasma cell disorders is associated with improved survival in MGUS, multiple myeloma, and systemic AL amyloidosis

The association between familial plasma cell disorders (PCD) and prognosis in patients with MGUS, multiple myeloma (MM), and systemic light chain (AL) amyloidosis has not been well described. This study retrospectively reviewed outcomes of 25,423 patients (16,744 MGUS, 6194 MM, 2955 AL amyloidosis). Overall, 2.7% of patients reported having a family member with a PCD (defined as MGUS, MM, or AL amyloidosis). Family history was documented in 94% of MGUS, 92% of MM, and 88% of AL amyloidosis patients. The overall survival was consistently longer in patients with versus without familial PCD (crude hazard ratios: 0.52, 95% CI 0.40-0.67, p < 0.001 for MGUS patients; 0.68, 95% CI 0.57-0.79, p < 0.001 for MM patients; 0.60, 95% CI 0.43-0.84, p = 0.003 for AL patients). This association remained consistent when adjusting for baseline patient and disease characteristics. In MGUS patients, the risk of progression to MM, AL amyloidosis, or a lymphoproliferative disorder was higher in patients with familial PCD when accounting for death as a competing risk (cause-specific HR 1.9, 95% 1.3-2.7, p < 0.001). This is the first study to demonstrate that in a cohort of MGUS, MM, and systemic AL amyloidosis, patients with a PCD family history have an improved overall survival.

A genetic risk score of alleles related to MGUS interacts with socioeconomic position in a population-based cohort

Environmental, genetic, and social factors are suggested to jointly influence monoclonal gammopathy of undetermined significance (MGUS), a precursor of multiple myeloma. Aim of this study was to investigate interactions between MGUS-related genetic variants and socioeconomic position (SEP) indicators education and income on MGUS in a population-based study. Two different MGUS-related genetic risk allele sum scores (GRS) were calculated based on recent genome-wide meta-analyses. Odds Ratios (OR) were estimated in 4329 participants including 238 MGUS cases to assess associations and multiplicative interaction. The relative excess risk due to interaction (RERI) was calculated to assess additive interaction. Both GRSs were associated with MGUS. A multiplicative interaction between one GRS and education was observed with genetic effects of OR 1.34 (95% CI 1.11–1.62) per risk allele in the highest and OR 1.06 (95% CI 0.86–1.31) in the lowest education group. A RERI of 0.10 (95% CI 0.05–0.14) also indicated additive interaction. Further, additive GRS by income interaction (RERI 0.07; 95% CI 0.01–0.13) for the same GRS was also indicated. Results indicate interaction between MGUS-related genetic risk and SEP. Non-genetic MGUS risk factors more common in higher education groups may influence the expression of MGUS-related genetic variants.

Sequencing at lymphoid neoplasm susceptibility loci maps six myeloma risk genes

Inherited genetic risk factors play a role in multiple myeloma (MM), yet considerable missing heritability exists. Rare risk variants at genome-wide association study (GWAS) loci are a new avenue to explore. Pleiotropy between lymphoid neoplasms (LNs) has been suggested in family history and genetic studies, but no studies have interrogated sequencing for pleiotropic genes or rare risk variants. Sequencing genetically enriched cases can help discover rarer variants. We analyzed exome sequencing in familial or early-onset MM cases to identify rare, functionally relevant variants near GWAS loci for a range of LNs. A total of 149 distinct and significant LN GWAS loci have been published. We identified six recurrent, rare, potentially deleterious variants within 5 kb of significant GWAS single nucleotide polymorphisms in 75 MM cases. Mutations were observed in BTNL2, EOMES, TNFRSF13B, IRF8, ACOXL and TSPAN32. All six genes replicated in an independent set of 255 early-onset MM or familial MM or precursor cases. Expansion of our analyses to the full length of these six genes resulted in a list of 39 rare and deleterious variants, seven of which segregated in MM families. Three genes also had significant rare variant burden in 733 sporadic MM cases compared with 935 control individuals: IRF8 (P = 1.0 × 10-6), EOMES (P = 6.0 × 10-6) and BTNL2 (P = 2.1 × 10-3). Together, our results implicate six genes in MM risk, provide support for genetic pleiotropy between LN subtypes and demonstrate the utility of sequencing genetically enriched cases to identify functionally relevant variants near GWAS loci.

Shaping the Treatment Paradigm Based on the Current Understanding of the Pathobiology of Multiple Myeloma: An Overview

Multiple myeloma is an incurable malignancy which despite progressive improvements in overall survival over the last decade remains characterised by recurrent relapse with progressively shorter duration of response and treatment-free intervals with each subsequent treatment. Efforts to unravel the complex and heterogeneous genomic alterations, the marked dysregulation of the immune system and the multifarious interplay between malignant plasma cells and those of the tumour microenvironment have not only led to improved understanding of myelomagenesis and disease progression but have facilitated the rapid development of novel therapeutics including immunotherapies and small molecules bringing us a step closer to therapies that no doubt will extend survival. Novel therapeutic combinations both in the upfront and relapsed setting as well as novel methods to assess response and guide management are rapidly transforming the management of myeloma.

Mouse tumor susceptibility genes identify drug combinations for multiple myeloma

Long-term genetic studies utilizing backcross and congenic strain analyses coupled with positional cloning strategies and functional studies identified Cdkn2a, Mtor, and Mndal as mouse plasmacytoma susceptibility/resistance genes. Tumor incidence data in congenic strains carrying the resistance alleles of Cdkn2a and Mtor led us to hypothesize that drug combinations affecting these pathways are likely to have an additive, if not synergistic effect in inhibiting tumor cell growth. Traditional and novel systems-level genomic approaches were used to assess combination activity, disease specificity, and clinical potential of a drug combination involving rapamycin/everolimus, an Mtor inhibitor, with entinostat, an histone deacetylase inhibitor. The combination synergistically repressed oncogenic MYC and activated the Cdkn2a tumor suppressor. The identification of MYC as a primary upstream regulator led to the identification of small molecule binders of the G-quadruplex structure that forms in the NHEIII region of the MYC promoter. These studies highlight the importance of identifying drug combinations which simultaneously upregulate tumor suppressors and downregulate oncogenes.

Second malignancies in multiple myeloma; emerging patterns and future directions

The changing landscape of treatment options for multiple myeloma has led to a higher proportion of patients achieving deep, long-lasting responses to therapy. With the associated improvement in overall survival, the development of subsequent second malignancies has become of increased significance. The risk of second malignancy after multiple myeloma is affected by a combination of patient-, disease- and therapy-related risk factors. This review discusses recent data refining our knowledge of these contributing factors, including current treatment modalities which increase risk (i.e. high-dose melphalan with autologous stem cell transplant and lenalidomide maintenance therapy). We highlight emerging data towards individualized risk- and response-adapted treatment strategies and discuss key areas requiring future research.

Next-Generation Sequencing for Clinical Management of Multiple Myeloma: Ready for Prime Time?

Personalized treatment is an attractive strategy that promises increased efficacy with reduced side effects in cancer. The feasibility of such an approach has been greatly boosted by next-generation sequencing (NGS) techniques, which can return detailed information on the genome and on the transcriptome of each patient's tumor, thus highlighting biomarkers of response or druggable targets that may differ from case to case. However, while the number of cancers sequenced is growing exponentially, much fewer cases are amenable to a molecularly-guided treatment outside of clinical trials to date. In multiple myeloma, genomic analysis shows a variety of gene mutations, aneuploidies, segmental copy-number changes, translocations that are extremely heterogeneous, and more numerous than other hematological malignancies. Currently, in routine clinical practice we employ reduced FISH panels that only capture three high-risk features as part of the R-ISS. On the contrary, recent advances have suggested that extending genomic analysis to the full spectrum of recurrent mutations and structural abnormalities in multiple myeloma may have biological and clinical implications. Furthermore, increased efficacy of novel treatments can now produce deeper responses, and standard methods do not have enough sensitivity to stratify patients in complete biochemical remission. Consequently, NGS techniques have been developed to monitor the size of the clone to a sensitivity of up to a cell in a million after treatment. However, even these techniques are not within reach of standard laboratories. In this review we will recapitulate recent advances in multiple myeloma genomics, with special focus on the ones that may have immediate translational impact. We will analyze the benefits and pitfalls of NGS-based diagnostics, highlighting crucial aspects that will need to be taken into account before this can be implemented in most laboratories. We will make the point that a new era in myeloma diagnostics and minimal residual disease monitoring is close and conventional genetic testing will not be able to return the required information. This will mandate that even in routine practice NGS should soon be adopted owing to a higher informative potential with increasing clinical benefits.

Genetic predisposition for multiple myeloma

Multiple myeloma (MM) is the second most common blood malignancy. Epidemiological family studies going back to the 1920s have provided evidence for familial aggregation, suggesting a subset of cases have an inherited genetic background. Recently, studies aimed at explaining this phenomenon have begun to provide direct evidence for genetic predisposition to MM. Genome-wide association studies have identified common risk alleles at 24 independent loci. Sequencing studies of familial cases and kindreds have begun to identify promising candidate genes where variants with strong effects on MM risk might reside. Finally, functional studies are starting to give insight into how identified risk alleles promote the development of MM. Here, we review recent findings in MM predisposition field, and highlight open questions and future directions.

LncRNA HOXB-AS1 promotes cell growth in multiple myeloma via FUT4 mRNA stability by ELAVL1

Multiple myeloma (MM) is defined as the second most common hematological tumor in the globe. Long noncoding RNAs (lncRNAs) have been reported to play stimulative or suppressive role in the progression of different carcinomas. The investigation of lncRNAs in MM is still inadequate. LncRNA HOXB cluster antisense RNA 1 (HOXB-AS1) was once revealed to facilitate glioma progression by affecting cellular activities of glioma cells. However, whether HOXB-AS1 participates in the development of MM still remains an enigma. In this study, we unveiled that HOXB-AS1 was highly expressed in MM and loss-of-function assays certified that HOXB-AS1 obstruction suppressed MM cell proliferation, and stimulated cell apoptosis. In addition, HOXB-AS1 could modulate fucosyltransferase 4 (FUT4) and FUT4-mediated Wnt/β-catenin pathway. In subsequence, it was observed from mechanism assays that HOXB-AS1 enhanced the interaction between ELAVL1 and FUT4 so as to stabilize FUT4 messenger RNA. In the end, rescue experiments affirmed that HOXB-AS1 affected the cell growth through FUT4 in MM. In conclusion, the whole modulation mechanism of HOXB-AS1/ELAVL1/FUT4 axis in MM was validated in this study, which suggested that HOXB-AS1 might function as a powerful and promising therapeutic biomarker for the clinical treatment of patients with MM.

Comprehensive detection of recurring genomic abnormalities: a targeted sequencing approach for multiple myeloma

Recent genomic research efforts in multiple myeloma have revealed clinically relevant molecular subgroups beyond conventional cytogenetic classifications. Implementing these advances in clinical trial design and in routine patient care requires a new generation of molecular diagnostic tools. Here, we present a custom capture next-generation sequencing (NGS) panel designed to identify rearrangements involving the IGH locus, arm level, and focal copy number aberrations, as well as frequently mutated genes in multiple myeloma in a single assay. We sequenced 154 patients with plasma cell disorders and performed a head-to-head comparison with the results from conventional clinical assays, i.e., fluorescent in situ hybridization (FISH) and single-nucleotide polymorphism (SNP) microarray. Our custom capture NGS panel had high sensitivity (>99%) and specificity (>99%) for detection of IGH translocations and relevant chromosomal gains and losses in multiple myeloma. In addition, the assay was able to capture novel genomic markers associated with poor outcome such as bi-allelic events involving TP53. In summary, we show that a multiple myeloma designed custom capture NGS panel can detect IGH translocations and CNAs with very high concordance in relation to FISH and SNP microarrays and importantly captures the most relevant and recurrent somatic mutations in multiple myeloma rendering this approach highly suitable for clinical application in the modern era.

Germline Risk Contribution to Genomic Instability in Multiple Myeloma

Genomic instability, a well-established hallmark of human cancer, is also a driving force in the natural history of multiple myeloma (MM) - a difficult to treat and in most cases fatal neoplasm of immunoglobulin producing plasma cells that reside in the hematopoietic bone marrow. Long recognized manifestations of genomic instability in myeloma at the cytogenetic level include abnormal chromosome numbers (aneuploidy) caused by trisomy of odd-numbered chromosomes; recurrent oncogene-activating chromosomal translocations that involve immunoglobulin loci; and large-scale amplifications, inversions, and insertions/deletions (indels) of genetic material. Catastrophic genetic rearrangements that either shatter and illegitimately reassemble a single chromosome (chromotripsis) or lead to disordered segmental rearrangements of multiple chromosomes (chromoplexy) also occur. Genomic instability at the nucleotide level results in base substitution mutations and small indels that affect both the coding and non-coding genome. Sometimes this generates a distinctive signature of somatic mutations that can be attributed to defects in DNA repair pathways, the DNA damage response (DDR) or aberrant activity of mutator genes including members of the APOBEC family. In addition to myeloma development and progression, genomic instability promotes acquisition of drug resistance in patients with myeloma. Here we review recent findings on the genetic predisposition to myeloma, including newly identified candidate genes suggesting linkage of germline risk and compromised genomic stability control. The role of ethnic and familial risk factors for myeloma is highlighted. We address current research gaps that concern the lack of studies on the mechanism by which germline risk alleles promote genomic instability in myeloma, including the open question whether genetic modifiers of myeloma development act in tumor cells, the tumor microenvironment (TME), or in both. We conclude with a brief proposition for future research directions, which concentrate on the biological function of myeloma risk and genetic instability alleles, the potential links between the germline genome and somatic changes in myeloma, and the need to elucidate genetic modifiers in the TME.

Inheritance of Susceptibility to Malignant Blood Disorders

Malignant blood disorders depend on heritable susceptibility genes and occur in familial aggregations. We suggest a model of transgenerational segregation of the susceptibility genes based on the study of malignant blood disorders in Norwegian and Danish families with unrelated parents, and in the inbred Faroese population with related parents. This model, consisting of parental genomic imprinting and mother-son microchimerism, can explain the male predominance in most of the diseases, the predominance of affected parent-offspring when parents are not related, and the different modes of segregation in males and females. The model displays a specific pattern in the distribution of affected relatives for each diagnosis, viz. a characteristic distribution in the pedigrees of family members with malignant blood disorder related to the proband. Three such patterns, each reflecting a specific transgenerational passage, were identified: (1) alterations in the number of affected relatives in paternal lines alone, e.g. in patterns for probands with multiple myeloma; (2) alterations in the number of affected relatives in both paternal and maternal lines for probands with chronic lymphocytic leukemia; and (3) no alterations in the numbers of male and female affected relatives in the parental lines, e.g. for probands with some types of malignant lymphoma.

Risk of MGUS in relatives of multiple myeloma cases by clinical and tumor characteristics

We and others have shown increased risk of monoclonal gammopathy of undetermined significance (MGUS) in first-degree relatives of patients with multiple myeloma (MM). Whether familial risk of MGUS differs by the MM proband's age at onset, tumor or clinical characteristics is unknown. MM and smoldering MM (SMM) cases (N = 430) were recruited from the Mayo Clinic in Rochester, Minnesota between 2005-2015. First-degree relatives over age 40 provided serum samples for evaluation of MGUS (N = 1179). Age and sex specific rates of MGUS among first-degree relatives were compared to a population-based sample. Cytogenetic subtypes were classified by Fluorescence in situ hybridization. MGUS was detected in 75 first-degree relatives for an age- and sex- adjusted prevalence of 5.8% (95% CI: 4.5-7.2). Prevalence of MGUS in first-degree relatives was 2.4 fold (95% CI: 1.9-2.9) greater than expected rates. Familial risk did not differ by proband's age at diagnosis, gender, isotype, IgH translocation, or trisomy. This study confirms first-degree relatives of MM cases have a significantly higher risk of MGUS compared to the general population, regardless of age, gender, or tumor characteristics. In selected situations, such as multiple affected first-degree relatives, screening of first-degree relatives of MM cases could be considered for follow-up and prevention strategies.

The multiple myeloma risk allele at 5q15 lowers ELL2 expression and increases ribosomal gene expression

Recently, we identified ELL2 as a susceptibility gene for multiple myeloma (MM). To understand its mechanism of action, we performed expression quantitative trait locus analysis in CD138⁺ plasma cells from 1630 MM patients from four populations. We show that the MM risk allele lowers ELL2 expression in these cells (P_combined = 2.5 × 10⁻²⁷; β_combined = −0.24 SD), but not in peripheral blood or other tissues. Consistent with this, several variants representing the MM risk allele map to regulatory genomic regions, and three yield reduced transcriptional activity in plasmocytoma cell lines. One of these (rs3777189-C) co-locates with the best-supported lead variants for ELL2 expression and MM risk, and reduces binding of MAFF/G/K family transcription factors. Moreover, further analysis reveals that the MM risk allele associates with upregulation of gene sets related to ribosome biogenesis, and knockout/knockdown and rescue experiments in plasmocytoma cell lines support a cause–effect relationship. Our results provide mechanistic insight into MM predisposition.

ELL2 was recently discovered as a susceptibility gene for multiple myeloma (MM). Here, they show that the MM risk allele lowers ELL2 expression in plasma cells, that it also upregulates gene sets related to ribosome biogenesis, and that one of the linked variants reduces binding of MAFF/G/K family transcription factors.

Novel pedigree analysis implicates DNA repair and chromatin remodeling in multiple myeloma risk

The high-risk pedigree (HRP) design is an established strategy to discover rare, highly-penetrant, Mendelian-like causal variants. Its success, however, in complex traits has been modest, largely due to challenges of genetic heterogeneity and complex inheritance models. We describe a HRP strategy that addresses intra-familial heterogeneity, and identifies inherited segments important for mapping regulatory risk. We apply this new Shared Genomic Segment (SGS) method in 11 extended, Utah, multiple myeloma (MM) HRPs, and subsequent exome sequencing in SGS regions of interest in 1063 MM / MGUS (monoclonal gammopathy of undetermined significance-a precursor to MM) cases and 964 controls from a jointly-called collaborative resource, including cases from the initial 11 HRPs. One genome-wide significant 1.8 Mb shared segment was found at 6q16. Exome sequencing in this region revealed predicted deleterious variants in USP45 (p.Gln691* and p.Gln621Glu), a gene known to influence DNA repair through endonuclease regulation. Additionally, a 1.2 Mb segment at 1p36.11 is inherited in two Utah HRPs, with coding variants identified in ARID1A (p.Ser90Gly and p.Met890Val), a key gene in the SWI/SNF chromatin remodeling complex. Our results provide compelling statistical and genetic evidence for segregating risk variants for MM. In addition, we demonstrate a novel strategy to use large HRPs for risk-variant discovery more generally in complex traits.

The impact of prior malignancies on second malignancies and survival in MM patients: a population-based study

In the present study, we aimed to evaluate 2 hypotheses. First, we hypothesize that prior malignancy is a proxy for genetic susceptibility that could be a risk factor for subsequent malignancy development in multiple myeloma (MM) patients. Second, we hypothesize that survival after MM is influenced by a prior malignancy. All patients diagnosed with MM from 1 January 1973 to 31 December 2010 were identified from the Swedish Cancer Register. Cox regression model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) where prior malignancy was compared in MM patients who developed a subsequent malignancy and MM patients who did not. In another Cox regression model, survival was compared in MM patients with and without a prior malignancy diagnosis. A total of 19 791 patients were diagnosed with MM. Patients with a prior malignancy diagnosis had a significantly increased risk of developing a subsequent malignancy compared with MM patients without (HR 1.42, 95% CI 1.23-1.65, P < .001). MM patients with a prior malignancy diagnosis had a significant 1.21-fold increased risk of death (95% CI 1.115-1.26, P < .001) compared with MM patients without. MM patients with 2 or more prior malignancy diagnoses had a 1.34-fold increased risk of death (95% CI 1.19-1.52, P < .001). In this large population-based study, we report that prior malignancy increases the risk of subsequent malignancy development in MM patients. Furthermore, we found that prior malignancy negatively impacts survival and that >1 prior malignancy reduces survival even further.

Genomewide association study on monoclonal gammopathy of unknown significance (MGUS)

OBJECTIVES

To identify germ line variants contributing to the development of monoclonal gammopathy of undetermined significance (MGUS), an asymptomatic premalignant precursor for multiple myeloma (MM).

METHODS

We conducted the first genomewide association study (GWAS) on MGUS on 243 German cases with a replication on 294 Czech cases. Identified loci were further analyzed in 1508 German MM patients. New MM loci recently reported in a meta-analysis were also tested in the MGUS GWAS.

RESULTS

In GWAS, we identified 10 loci contributing to development of MGUS at P-value threshold of 10^-5 . The Czech cohort gave support for two associations (6q26, rs6933936; 7p21.3 rs10251201). In GWAS, rs974120 (8p23.2) reached genomewide significance (P=2.94×10^-9 ), with a nominal significance in MM. The locus of rs974120 shows marks of transcriptional activity in leukemia according to ENCODE data. rs10251201 (7p21.3), rs9318227 (13q22.1), and rs10405859 (19q13.32) were associated with markers related to leukemogenesis and immune and inflammatory responses. Two newly identified candidate loci for MM, rs1948915 (8q24.21) and rs8058578 (16p11.2), were nominally associated with MGUS.

CONCLUSIONS

These data allow a cautious first proposal for a germ line architecture of MGUS with links to leukemia and autoimmune conditions, the latter agreeing with a family study showing clustering of MGUS with autoimmune diseases.

Direct evidence for a polygenic etiology in familial multiple myeloma

Although common risk alleles for multiple myeloma (MM) were recently identified, their contribution to familial MM is unknown. Analyzing 38 familial cases identified primarily by linking Swedish nationwide registries, we demonstrate an enrichment of common MM risk alleles in familial compared with 1530 sporadic cases (P = 4.8 × 10^-2 and 6.0 × 10^-2, respectively, for 2 different polygenic risk scores) and 10 171 population-based controls (P = 1.5 × 10^-4 and 1.3 × 10^-4, respectively). Using mixture modeling, we estimate that about one-third of familial cases result from such enrichments. Our results provide the first direct evidence for a polygenic etiology in a familial hematologic malignancy.

Increased incidence of bladder cancer, lymphoid leukaemia, and myeloma in a cohort of Queensland melanoma families

Familial cancer risk has been proposed as a shared feature of many cancers, and overall susceptibility is influenced by combinations of low to moderate risk polymorphisms, rare high penetrance germline mutations, and modulation of risk by environmental and genetic factors. Clustering of melanoma occurs in approximately 10 % of families, and an over-representation of additional cancers has been noticed in some 'melanoma' families. The degree to which other cancers aggregate in families affected by melanoma has not been well defined. Therefore, this study aimed to assess the risk of cancers other than melanoma in a cohort of 178 'intermediate risk' melanoma families, not selected for specific genetic mutations. Families designated as 'intermediate risk' had two first degree relatives (FDRs) affected by melanoma when ascertained between 1982 and 1990, and were followed up over a 33 year period to assess new occurrences of cancer. We included 414 melanoma cases and 529 FDRs, comprising 25,264 person years of observation. Standardised incidence ratios and their 95 % confidence intervals were calculated for all invasive cancers, comparing observed to expected cases of cancer based on age and sex specific incidence rates for the Queensland population. Statistically significant increases were found for bladder cancer in females (observed, 7; expected, 1.99; SIR, 3.52; 95 % CI 1.41-7.25), lymphoid leukaemia in females (observed, 6; expected, 1.75; SIR, 3.43; 95 % CI 1.26-7.46), and myeloma in female melanoma cases (observed, 4; expected, 0.82; SIR, 4.89; 95 % CI 1.33-12.52). Over-representation of bladder cancer, lymphoid leukaemia, and myeloma in females of the cohort may suggest sex-dependent co-modifiers, and it is possible that specific combinations of polymorphisms predispose to certain cancer types.

Association of IL-6 Promoter and Receptor Polymorphisms with Multiple Myeloma Risk: A Systematic Review and Meta-Analysis

BACKGROUND

A number of studies show that the pleiotropic cytokine interleukin-6 (IL-6) plays an important role in the pathogenesis of multiple myeloma (MM). However, whether MM risk is associated with IL-6 genetic variability remains uncertain.

OBJECTIVE

The aim of our study was to evaluate the association between two different IL-6 polymorphisms (located in the IL-6 promoter and receptor, respectively) and the risk of developing MM using a meta-analytic approach.

MATERIALS AND METHODS

A systematic search for studies on the association of IL-6/IL-6R single-nucleotide polymorphisms with susceptibility to MM was conducted in PubMed, Cochrane Library, Embase, CNKI (Chinese) and Wanfang (Chinese) Digital Dissertations Databases from inception through November 2014. A meta-analysis was performed and results were presented as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of eight case-control studies on the IL-6 promoter polymorphism and three studies on the IL-6 receptor (IL-6R) polymorphism were included. No significant association was found between the IL-6 promoter rs1800795 (G>C) polymorphism and MM susceptibility. A significantly increased risk of MM was observed with the IL-6R rs8192284 (A>C) polymorphism. In subgroup analyses, grouped by ethnicity, region, quality of studies, and Hardy-Weinberg equilibrium of control group, similar results were found.

CONCLUSION

Unlike the IL-6 promoter rs1800795 (G>C) polymorphism, the IL-6R rs8192284 (A>C) polymorphism may be associated with MM risk. However, large-scale studies are needed to validate our findings since they are based on a relatively small number of studies.

MYC amplifications in myeloma cell lines: correlation with MYC-inhibitor efficacy

In multiple myeloma, elevated MYC expression is related to disease initiation and progression. We found that in myeloma cell lines, MYC gene amplifications were common and correlated with MYC mRNA and protein. In primary cell samples MYC mRNA levels were also relatively high; however gene copy number alterations were uncommon. Elevated levels of MYC in primary myeloma cells have been reported to arise from complex genetic aberrations and are more common than previously thought. Thus, elevated MYC expression is achieved differently in myeloma cell lines and primary cells. Sensitivity of myeloma cell lines to the MYC inhibitor 10058-F4 correlated with MYC expression, supporting that the activity of 10058-F4 was through specific inhibition of MYC.

Genome-wide association study identifies multiple susceptibility loci for multiple myeloma

Multiple myeloma (MM) is a plasma cell malignancy with a significant heritable basis. Genome-wide association studies have transformed our understanding of MM predisposition, but individual studies have had limited power to discover risk loci. Here we perform a meta-analysis of these GWAS, add a new GWAS and perform replication analyses resulting in 9,866 cases and 239,188 controls. We confirm all nine known risk loci and discover eight new loci at 6p22.3 (rs34229995, P=1.31 × 10(-8)), 6q21 (rs9372120, P=9.09 × 10(-15)), 7q36.1 (rs7781265, P=9.71 × 10(-9)), 8q24.21 (rs1948915, P=4.20 × 10(-11)), 9p21.3 (rs2811710, P=1.72 × 10(-13)), 10p12.1 (rs2790457, P=1.77 × 10(-8)), 16q23.1 (rs7193541, P=5.00 × 10(-12)) and 20q13.13 (rs6066835, P=1.36 × 10(-13)), which localize in or near to JARID2, ATG5, SMARCD3, CCAT1, CDKN2A, WAC, RFWD3 and PREX1. These findings provide additional support for a polygenic model of MM and insight into the biological basis of tumour development.

The Incidence of Senile Cataract and Glaucoma is Increased in Patients with Plasma Cell Dyscrasias: Etiologic Implications

Plasma cell dyscrasias, including monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM), Waldenström macroglobulinemia (WM) and light chain AL amyloidosis, are characterized by clonal expansion of plasma cells which produce a vast amount of an immunoglobulin-derived M-protein. We noted that MGUS diagnosis often coincided with diagnoses of senile cataract and glaucoma and tested the associations of MGUS, MM, WM and AL amyloidosis with subsequent eye diseases identified from the Swedish patient registers between 1997 and 2012. Standardized incidence ratios (SIRs) for senile cataract was significantly increased to 1.80 after MGUS, 1.70 after MM, 1.85 after WM and 2.31 after AL amyloidosis. The SIR for glaucoma was 1.60 after MGUS, 1.76 after WM and 2.18 after AL amyloidosis. All SIRs decreased systematically from age below 60 years to over 79 years, but most risks were also significant in age group over 79 years. The M-protein and the related increase in blood viscosity could be a novel etiologic discovery for these common eye diseases. As MGUS prevalence is around 3% at 60 years and close to 10% at age over 80 years, its contribution to the eye disease burden is expected to be remarkably high.

Rare SNPs in receptor tyrosine kinases are negative outcome predictors in multiple myeloma

Multiple myeloma (MM) is a plasma cell disorder that is characterized by a great genetic heterogeneity. Recent next generation sequencing studies revealed an accumulation of tumor-associated mutations in receptor tyrosine kinases (RTKs) which may also contribute to the activation of survival pathways in MM. To investigate the clinical role of RTK-mutations in MM, we deep-sequenced the coding DNA-sequence of EGFR, EPHA2, ERBB3, IGF1R, NTRK1 and NTRK2 which were previously found to be mutated in MM, in 75 uniformly treated MM patients of the "Deutsche Studiengruppe Multiples Myelom". Subsequently, we correlated the detected mutations with common cytogenetic alterations and clinical parameters. We identified 11 novel non-synonymous SNVs or rare patient-specific SNPs, not listed in the SNP databases 1000 genomes and dbSNP, in 10 primary MM cases. The mutations predominantly affected the tyrosine-kinase and ligand-binding domains and no correlation with cytogenetic parameters was found. Interestingly, however, patients with RTK-mutations, specifically those with rare patient-specific SNPs, showed a significantly lower overall, event-free and progression-free survival. This indicates that RTK SNVs and rare patient-specific RTK SNPs are of prognostic relevance and suggests that MM patients with RTK-mutations could potentially profit from treatment with RTK-inhibitors.

Risk of Second Primary Cancers in Multiple Myeloma Survivors in German and Swedish Cancer Registries

We aimed at investigating the distribution and risk of second primary cancers (SPCs) in multiple myeloma (MM) survivors in Germany and Sweden to provide etiological understanding of SPCs and insight into their incidence rates and recording practices. MM patients diagnosed in 1997–2010 at age ≥15 years were selected from the Swedish (nationwide) and 12 German cancer registries. Standardized incidence ratios (SIRs) were used to assess risk of a specific SPC compared to risk of the same first cancer in the corresponding background population. Among 18,735 survivors of first MM in Germany and 7,560 in Sweden, overall 752 and 349 SPCs were recorded, respectively. Significantly elevated SIRs of specific SPCs were observed for acute myeloid leukemia (AML; SIR = 4.9) in Germany and for kidney cancer (2.3), AML (2.3) and nervous system cancer (1.9) in Sweden. Elevated risk for AML was more pronounced in the earlier diagnosis period compared to the later, i.e., 9.7 (4.2–19) for 1997–2003 period versus 3.5 (1.5–6.9) for 2004–2010 in Germany; 3.8 (1.4–8.3) for 1997–2003 versus 2.2 (0.3–7.8) for 2004–2010 in Sweden. We found elevated risk for AML for overall, early diagnosis periods and longer follow-up times in both populations, suggesting possible side effects of treatment for MM patients.

Future Directions in the Evaluation and Treatment of Precursor Plasma Cell Disorders

Multiple myeloma (MM) is an incurable disease that progresses from a premalignant stage termed monoclonal gammopathy of undetermined significance (MGUS) and an intermediate stage of smoldering multiple myeloma (SMM). Recent major advances in therapy with more effective and less toxic treatments have brought reconsideration of early therapeutic intervention in management of SMM, with the goal of reducing progression of the disease before the occurrence of end-organ damage to MM and improving survival. Key to this effort is accurate identification of patients at high risk of progression who would truly benefit from early intervention. In this review, we discuss the current definitions, risk factors, risk stratification, prognosis, and management of MGUS and SMM, as well as new emerging therapeutic options under active investigation.

Mechanisms and Clinical Applications of Genome Instability in Multiple Myeloma

Ongoing genomic instability represents a hallmark of multiple myeloma (MM) cells, which manifests largely as whole chromosome- or translocation-based aneuploidy. Importantly, although it supports tumorigenesis, progression and, response to treatment in MM patients, it remains one of the least understood components of malignant transformation in terms of molecular basis. Therefore these aspects make the comprehension of genomic instability a pioneering strategy for novel therapeutic and clinical speculations to use in the management of MM patients. Here we will review mechanisms mediating genomic instability in MM cells with an emphasis placed on pathogenic mutations affecting DNA recombination, replication and repair, telomere function and mitotic regulation of spindle attachment, centrosome function, and chromosomal segregation. We will discuss the mechanisms by which genetic aberrations give rise to multiple pathogenic events required for myelomagenesis and conclude with a discussion of the clinical applications of these findings in MM patients.

Search for familial clustering of multiple myeloma with any cancer

Multiple myeloma (MM) is a disease of immunoglobulin-producing plasma cells, which reside mainly in the bone marrow. Family members of MM patients are at a risk of MM, but whether other malignancies are in excess in family members is not established and is the aim of this study. MM patients (24 137) were identified from the Swedish Cancer Registry from years 1958 to 2012. Relative risks (RRs) were calculated for MM defined by any cancer diagnosed in first-degree relatives and compared with individuals whose relatives had no cancer. MM was reliably associated with relative's colorectal, breast and prostate cancers, non-thyroid endocrine tumors, leukemia and cancer of unknown primary; in addition, MM was associated with subsites of bone and connective tissue tumors and of non-Hodgkin lymphoma, including lymphoplasmacytic lymphoma/Waldenström macroglobulinema (RR 3.47). MM showed a strong association (RR 1.91) in colorectal cancer families, possibly as part of an unidentified syndrome. All the associations of MM with discordant cancers are novel suggesting that MM shares genetic susceptibility with many cancers. The associations of MM bone and connective tissue tumors were supported by at least two independent results. Whether the results signal bone-related biology shared by MM and these tumors deserves further study.

Implementation of genome-wide complex trait analysis to quantify the heritability in multiple myeloma

A sizeable fraction of multiple myeloma (MM) is expected to be explained by heritable factors. Genome-wide association studies (GWAS) have successfully identified a number of common single-nucleotide polymorphisms (SNPs) influencing MM risk. While these SNPs only explain a small proportion of the genetic risk it is unclear how much is left to be detected by other, yet to be identified, common SNPs. Therefore, we applied Genome-Wide Complex Trait Analysis (GCTA) to 2,282 cases and 5,197 controls individuals to estimate the heritability of MM. We estimated that the heritability explained by known common MM risk SNPs identified in GWAS was 2.9% (± 2.4%), whereas the heritability explained by all common SNPs was 15.2% (± 2.8%). Comparing the heritability explained by the common variants with that from family studies, a fraction of the heritability may be explained by other genetic variants, such as rare variants. In summary, our results suggest that known MM SNPs only explain a small proportion of the heritability and more common SNPs remain to be identified.

Large registry analysis to accurately define second malignancy rates and risks in a well-characterized cohort of 744 consecutive multiple myeloma patients followed-up for 25 years

Additional malignancies in multiple myeloma patients after first-line and maintenance treatment have been observed, questioning whether specific risks exist. Second primary malignancies have also gained attention since randomized data showed associations to newer drugs. We have conducted this large registry analysis in 744 consecutive patients and analyzed: 1) frequency and onset of additional malignancies; and 2) second primary malignancy- and myeloma-specific risks. We assessed the frequency of additional malignancies in terms of host-, myeloma- and treatment-specific characteristics. To compare these risks, we estimated cumulative incidence rates for second malignancies and myeloma with Fine and Gray regression models taking into account competing risks. Additional malignancies were found in 118 patients: prior or synchronous malignancies in 63% and subsequent in 37%. Cumulative incidence rates for second malignancies were increased in IgG-myeloma and decreased in bortezomib-treated patients (P<0.05). Cumulative incidence rates for myeloma death were increased with higher stage and age, but decreased in IgG-subtypes and due to anti-myeloma treatment (P<0.05). Cytogenetics in patients acquiring second primary malignancies were predominantly favorable, suggesting that indolent myeloma and long disease latency may allow the manifestation of additional malignancies. An assessment of the Surveillance, Epidemiology, and End Result Program of the National Cancer Institute and our data with long-term follow up of 25 years confirmed a prevalence of second malignancy of 10% at 25 years, whereas death from myeloma decreased from 90% to 83%, respectively. Our important findings widen our knowledge of second malignancies and show that they are of increasing relevance as the prognosis in myeloma improves and mortality rates decrease.

Risk Factors for Multiple Myeloma: A Systematic Review of Meta-Analyses

The epidemiology of multiple myeloma (MM) is an increasingly investigated field, with many controversies. This systematic review aims to synthesize meta-analyses examining risk factors for MM so as to provide a comprehensive, parsimonious summary of the current evidence. Eligible meta-analyses were sought in PubMed adopting a predefined algorithm, without any restriction of publication language; end-of-search date was October 10, 2014. The selection of eligible studies and data extraction were performed by working in pairs, independently and blindly to each other; in case of disagreement, consensus with the whole team was reached. Among the 22 ultimately included meta-analyses, 9 examined occupational factors, 4 assessed aspects of lifestyle (smoking, alcohol, body mass index), 5 evaluated the presence of other diseases, and 4 addressed genetic factors as potential risk factors of MM. A vast compendium of significant associations arose, including farming, occupation as a firefighter, occupation as a hairdresser, exposures to chemicals or pesticides, overweight and obesity, patterns of alcohol intake, pernicious anemia, ankylosing spondylitis, gene promoter methylation, and polymorphisms. In conclusion, MM is a multifactorial disease, encompassing a wide variety of risk factors that span numerous life aspects. Further accumulation of evidence through meta-analyses is anticipated in this rapidly growing field.

Meta-analysis of the association of MTHFR polymorphisms with multiple myeloma risk

The association of methylenetetrahydrofolate reductase (MTHFR) polymorphisms with multiple myeloma (MM) risk has been explored, but the results remain controversial. Thus, a meta-analysis was performed to provide a comprehensively estimate. The case-control studies about MTHFR C677T and A1298C polymorphisms with MM risk were collected by searching PubMed, Elsevier, China National Knowledge Infrastructure and Wanfang Databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were applied to assess the strength of association. Overall, no significant association was found between MTHFR A1298C polymorphism and MM risk under all four genetic models (AC vs. AA, OR = 0.99, 95%CI = 0.82-1.20; CC vs. AA, OR = 1.14, 95%CI = 0.77-1.68; recessive model, OR = 1.10, 95%CI = 0.76-1.59; dominant model, OR = 1.01, 95%CI = 0.84-1.22). The risk was also not significantly altered for C677T polymorphism and MM in overall comparisons (CT vs. CC, OR = 1.04, 95%CI = 0.93-1.17; TT vs. CC, OR = 1.16, 95%CI = 0.98-1.37; recessive model, OR = 1.13, 95%CI = 0.98-1.32; dominant model, OR = 1.07, 95%CI = 0.96-1.20). In subgroup analyses by ethnicity, no significant association was observed in both Caucasians and Asians. This meta-analysis suggested that MTHFR polymorphisms were not associated with MM risk.

Variants in ELL2 influencing immunoglobulin levels associate with multiple myeloma

Multiple myeloma (MM) is characterized by an uninhibited, clonal growth of plasma cells. While first-degree relatives of patients with MM show an increased risk of MM, the genetic basis of inherited MM susceptibility is incompletely understood. Here we report a genome-wide association study in the Nordic region identifying a novel MM risk locus at ELL2 (rs56219066T; odds ratio (OR)=1.25; P=9.6 × 10(-10)). This gene encodes a stoichiometrically limiting component of the super-elongation complex that drives secretory-specific immunoglobulin mRNA production and transcriptional regulation in plasma cells. We find that the MM risk allele harbours a Thr298Ala missense variant in an ELL2 domain required for transcription elongation. Consistent with a hypomorphic effect, we find that the MM risk allele also associates with reduced levels of immunoglobulin A (IgA) and G (IgG) in healthy subjects (P=8.6 × 10(-9) and P=6.4 × 10(-3), respectively) and, potentially, with an increased risk of bacterial meningitis (OR=1.30; P=0.0024).

Genomic heterogeneity in multiple myeloma

Multiple myeloma (MM) is an incurable malignancy in majority of patients characterized by clonal proliferation of plasma cells. To date, treatment is established based on general conditions and age of patients. However, MM is a heterogeneous disease, featured by various subtypes and different outcomes. Thus, the understanding of MM biology is currently a major challenge to eventually cure the disease. During the last decade, karyotype studies and gene expression profiling have identified robust prognostic markers as well as a widespread genomic landscape. More recently, studies of epigenetic, transcriptional modifications and next generation sequencing have allowed characterization of critical genes and pathways, clonal heterogeneity and mutational profiles involved in myelomagenesis. Altogether, these findings constitute important tools to develop new targeted and personalized therapies in MM.