Assessment of Total Lesion Glycolysis by 18F FDG PET/CT Significantly Improves Prognostic Value of GEP and ISS in Myeloma

Purpose: Fluorine-18 fluorodeoxyglucose positron emission tomography with CT attenuation correction (¹⁸F-FDG PET/CT) is useful in the detection and enumeration of focal lesions and in semiquantitative characterization of metabolic activity (glycolytic phenotype) by calculation of glucose uptake. Total lesion glycolysis (TLG) and metabolic tumor volume (MTV) have the potential to improve the value of this approach and enhance the prognostic value of disease burden measures. This study aims to determine whether TLG and MTV are associated with progression-free survival (PFS) and overall survival (OS), and whether they improve risk assessments such as International Staging System (ISS) stage and GEP70 risk.Experimental Design: 192 patients underwent whole body PET/CT in the Total Therapy 3A (TT3A) trial and were evaluated using three-dimensional region-of-interest analysis with TLG, MTV, and standard measurement parameters derived for all focal lesions with peak SUV above the background red marrow signal.Results: In multivariate analysis, baseline TLG > 620 g and MTV > 210 cm³ remained a significant factor of poor PFS and OS after adjusting for baseline myeloma variables. Combined with the GEP70 risk score, TLG > 205 g identifies a high-risk-behaving subgroup with poor expected survival. In addition, TLG > 205 g accurately divides ISS stage II patients into two subgroups with similar outcomes to ISS stage I and ISS stage III, respectively.Conclusions: TLG and MTV have significant survival implications at baseline and offer a more precise quantitation of the glycolytic phenotype of active disease. These measures can be assessed more readily than before using FDA-approved software and should be standardized and incorporated into clinical trials moving forward. Clin Cancer Res; 23(8); 1981-7. ©2016 AACR.

The Kinetic Stability of a Full-Length Antibody Light Chain Dimer Determines whether Endoproteolysis Can Release Amyloidogenic Variable Domains

Light chain (LC) amyloidosis (AL amyloidosis) appears to be caused by the misfolding, or misfolding and aggregation of an antibody LC or fragment thereof and is fatal if untreated. LCs are secreted from clonally expanded plasma cells, generally as disulfide-linked dimers, with each monomer comprising one constant and one variable domain. The energetic contribution of each domain and the role of endoproteolysis in AL amyloidosis remain unclear. To investigate why only some LCs form amyloid and cause organ toxicity, we measured the aggregation propensity and kinetic stability of LC dimers and their associated variable domains from AL amyloidosis patients and non-patients. All the variable domains studied readily form amyloid fibrils, whereas none of the full-length LC dimers, even those from AL amyloidosis patients, are amyloidogenic. Kinetic stability-that is, the free energy difference between the native state and the unfolding transition state-dictates the LC's unfolding rate. Full-length LC dimers derived from AL amyloidosis patients unfold more rapidly than other full-length LC dimers and can be readily cleaved into their component domains by proteases, whereas non-amyloidogenic LC dimers are more kinetically stable and resistant to endoproteolysis. Our data suggest that amyloidogenic LC dimers are kinetically unstable (unfold faster) and are thus susceptible to endoproteolysis that results in the release amyloidogenic LC fragments, whereas other LCs are not as amenable to unfolding and endoproteolysis and are therefore aggregation resistant. Pharmacologic kinetic stabilization of the full-length LC dimer could be a useful strategy to treat AL amyloidosis.

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.

Genomewide profiling of copy-number alteration in monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a benign condition with an approximate 1% annual risk of symptomatic plasma cell disorder development, mostly to multiple myeloma (MM). We performed genomewide screening of copy-number alterations (CNAs) in 90 MGUS and 33 MM patients using high-density DNA microarrays. We identified CNAs in a smaller proportion of MGUS (65.6%) than in MM (100.0%, P = 1.31 × 10^-5 ) and showed median number of CNAs is lower in MGUS (3, range 0-22) than in MM (13, range 4-38, P = 1.82 × 10^-10 ). In the MGUS cohort, the most frequent losses were located at 1p (5.6%), 6q (6.7%), 13q (30.0%), 14q (14.4%), 16q (8.9%), 21q (5.6%), and gains at 1q (23.3%), 2p (6.7%), 6p (13.3%), and Xq (7.8%). Hyperdiploidy was detected in 38.9% of MGUS cases, and the most frequent whole chromosome gains were 3 (25.6%), 5 (23.3%), 9 (37.8%), 15 (23.3%), and 19 (32.2%). We also identified CNAs such as 1p, 6q, 8p, 12p, 13q, 16q losses, 1q gain and hypodiploidy, which are potentially associated with an adverse prognosis in MGUS. In summary, we showed that MGUS is similar to MM in that it is a genetically heterogeneous disorder, but overall cytogenetic instability is lower than in MM, which confirms that genetic abnormalities play important role in monoclonal gammopathies.

The combination of HDAC and aminopeptidase inhibitors is highly synergistic in myeloma and leads to disruption of the NFκB signalling pathway

There is a growing body of evidence supporting the use of epigenetic therapies in the treatment of multiple myeloma. We show the novel HDAC inhibitor CHR-3996 induces apoptosis in myeloma cells at concentrations in the nanomolar range and with apoptosis mediated by p53 and caspase pathways. In addition, HDAC inhibitors are highly synergistic, both in vitro and in vivo, with the aminopeptidase inhibitor tosedostat (CHR-2797). We demonstrate that the basis for this synergy is a consequence of changes in the levels of NFκB regulators BIRC3/cIAP2, A20, CYLD, and IκB, which were markedly affected by the combination. When co-administered the HDAC and aminopeptidase inhibitors caused rapid nuclear translocation of NFκB family members p65 and p52, following activation of both canonical and non-canonical NFκB signalling pathways. The subsequent up-regulation of inhibitors of NFκB activation (most significantly BIRC3/cIAP2) turned off the cytoprotective effects of the NFκB signalling response in a negative feedback loop. These results provide a rationale for combining HDAC and aminopeptidase inhibitors clinically for the treatment of myeloma patients and support the disruption of the NFκB signalling pathway as a therapeutic strategy.

The diagnosis and interventional management of pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVM) describe a broad group of complex vascular malformations, often associated with multi-system diseases and with palliated complex congenital heart disease. They can have major clinical consequences, resulting in strokes, cerebral abscesses, cyanosis and, infrequently, rupture into the pleural space. The best approach to their investigation and interventional treatment is via a multidisciplinary pathway which should be focused in high-volume centres with on-site thoracic and cardiovascular surgical back-up. The availability of computed tomography (CT) and a broad cathlab inventory aid procedural planning and success. The results of interventional treatment are very encouraging and are applicable to an increasingly broad group of patients thanks to improvements in interventional techniques and a significant expansion of the inventory of vascular occlusion devices.

Genetic factors influencing the risk of multiple myeloma bone disease

A major complication of multiple myeloma (MM) is the development of osteolytic lesions, fractures and bone pain. To identify genetic variants influencing the development of MM bone disease (MBD), we analyzed MM patients of European ancestry (totaling 3774), which had been radiologically surveyed for MBD. Each patient had been genotyped for ~6 00 000 single-nucleotide polymorphisms with genotypes for six million common variants imputed using 1000 Genomes Project and UK10K as reference. We identified a locus at 8q24.12 for MBD (rs4407910, OPG/TNFRSF11B, odds ratio=1.38, P=4.09 × 10(-9)) and a promising association at 19q13.43 (rs74676832, odds ratio=1.97, P=9.33 × 10(-7)). Our findings demonstrate that germline variation influences MBD and highlights the importance of RANK/RANKL/OPG pathway in MBD development. These findings will contribute to the development of future strategies for prevention of MBD in the early precancerous phases of MM.

Monoclonal antibody therapy in multiple myeloma: where do we stand and where are we going?

Multiple myeloma is a plasma cell malignancy that is characterized by refractory and relapsing course of disease. Despite the introduction of high-dose chemotherapy in combination with autologous stem cell transplantation and innovative agents such as proteasome inhibitors and immunomodulatory drugs, achieving cure in multiple myeloma is a challenging endeavor. In the last couple of years, enormous advances were made in implementing monoclonal antibody therapy in multiple myeloma. A large number of preclinical and clinical studies have been introduced successfully, demonstrating a safe and efficient administration of monoclonal antibodies in multiple myeloma. In particular, the application of monoclonal antibodies in combination with immunomodulatory drugs, proteasome inhibitors, corticosteroids or conventional chemotherapy seem to be promising and will expand the treatment arsenal for patients with multiple myeloma.

Genome-wide association study identifies variation at 6q25.1 associated with survival in multiple myeloma

Survival following a diagnosis of multiple myeloma (MM) varies between patients and some of these differences may be a consequence of inherited genetic variation. In this study, to identify genetic markers associated with MM overall survival (MM-OS), we conduct a meta-analysis of four patient series of European ancestry, totalling 3,256 patients with 1,200 MM-associated deaths. Each series is genotyped for ∼600,000 single nucleotide polymorphisms across the genome; genotypes for six million common variants are imputed using 1000 Genomes Project and UK10K as the reference. The association between genotype and OS is assessed by Cox proportional hazards model adjusting for age, sex, International staging system and treatment. We identify a locus at 6q25.1 marked by rs12374648 associated with MM-OS (hazard ratio=1.34, 95% confidence interval=1.22-1.48, P=4.69 × 10(-9)). Our findings have potential clinical implications since they demonstrate that inherited genotypes can provide prognostic information in addition to conventional tumor acquired prognostic factors.

Profound impact of sample processing delay on gene expression of multiple myeloma plasma cells

Background

Gene expression profiling (GEP) has significantly contributed to the elucidation of the molecular heterogeneity of multiple myeloma plasma cells (MMPC) and only recently it has been recommended for risk stratification. Prior to GEP MMPC need to be enriched resulting in an inability to immediately freeze bone marrow aspirates or use RNA stabilization reagents. As a result in multi-center MM trials sample processing delay due to shipping may be an important confounder of molecular analyses and risk stratification based on GEP data.

Results

We compared GEP data of 145 in-house and 246 shipped samples and detected 3301 down-regulated and 3501 up-regulated genes in shipped samples. For 3994 genes we confirmed differential expression in an independent set of 85 in-house and 97 shipped samples. Differentially expressed genes were enriched in processes like ribosome biogenesis, cell cycle, and apoptosis. Among GEP based risk predictors the IFM-15 seemed to underestimate high risk in shipped samples, whereas the GEP70 and the EMC-92 gene signatures were more robust. In order to provide a tool to assess the “shipping effect” in public repositories, we generated a 17-gene predictor for shipped samples with a 10-fold cross validation error rate of 0.06 for the training set and an error rate of 0.15 for the validation set.

Conclusion

Sample processing delay significantly influences GEP of MMPC, implying it should be avoided if samples were used for risk stratification.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-015-0161-6) contains supplementary material, which is available to authorized users.

Mutational Spectrum, Copy Number Changes, and Outcome: Results of a Sequencing Study of Patients With Newly Diagnosed Myeloma

PURPOSE

At the molecular level, myeloma is characterized by copy number abnormalities and recurrent translocations into the immunoglobulin heavy chain locus. Novel methods, such as massively parallel sequencing, have begun to describe the pattern of tumor-acquired mutations, but their clinical relevance has yet to be established.

METHODS

We performed whole-exome sequencing for 463 patients who presented with myeloma and were enrolled onto the National Cancer Research Institute Myeloma XI trial, for whom complete molecular cytogenetic and clinical outcome data were available.

RESULTS

We identified 15 significantly mutated genes: IRF4, KRAS, NRAS, MAX, HIST1H1E, RB1, EGR1, TP53, TRAF3, FAM46C, DIS3, BRAF, LTB, CYLD, and FGFR3. The mutational spectrum is dominated by mutations in the RAS (43%) and nuclear factor-κB (17%) pathways, but although they are prognostically neutral, they could be targeted therapeutically. Mutations in CCND1 and DNA repair pathway alterations (TP53, ATM, ATR, and ZNFHX4 mutations) are associated with a negative impact on survival. In contrast, those in IRF4 and EGR1 are associated with a favorable overall survival. We combined these novel mutation risk factors with the recurrent molecular adverse features and international staging system to generate an international staging system mutation score that can identify a high-risk population of patients who experience relapse and die prematurely.

CONCLUSION

We have refined our understanding of genetic events in myeloma and identified clinically relevant mutations that may be used to better stratify patients at presentation.

Hybrid Procedure for Neonates With Hypoplastic Left Heart Syndrome at High-Risk for Norwood: Midterm Outcomes

BACKGROUND

Hybrid procedure offers patients with severe congenital heart disease an alternative initial procedure to conventional surgical reconstruction. We report the midterm outcomes of a cohort of neonates who had a hybrid procedure for variants of hypoplastic left heart syndrome because they were at high risk for the Norwood procedure.

METHODS

Between December 2005 and January 2013, 41 neonates underwent bilateral pulmonary artery banding followed by ductal stenting by means of a sternotomy at a median age of 6 days (range, 2 to 18 days) and weight of 2.6 kg (range, 1.5 to 3.7 kg). Thirty-five patients had hypoplastic left heart syndrome, and 6 patients had critical aortic stenosis with hypoplastic left ventricle. Primary indications for the hybrid procedure were low birth weight in 17 patients, hypoplastic left ventricle with the possibility of later biventricular repair in 6 patients, intact or near-intact atrial septum in 5 patients, and poor patient condition in 13 patients. Echocardiographic, angiographic, operative, and clinical data were reviewed. Outcomes were summarized with descriptive statistics and risk factors for mortality identified.

RESULTS

All but 6 patients had an antenatal diagnosis, and 24 patients were from other congenital cardiac centers. Nine patients had perioperative balloon aortic valvuloplasty, 1 patient had fetal balloon aortic valvuloplasty, and 17 patients had intervention to their atrial septum (41.4%). There were 9 inpatient deaths (21.9%) and 4 interstage deaths (9.8%) after the hybrid procedure. Twenty-eight patients subsequently underwent either the Norwood procedure (11 patients), combined stage I and II (14 patients), or biventricular repair (3 patients). No patient had heart transplantation. Among the patients who had combined stage I and II as a second procedure after the hybrid procedure, there were 2 early deaths, 1 late death before the Fontan, and 1 late death after the Fontan completion after combined stage I and II. All patients who had subsequent Norwood procedure were midterm survivors. Three of the 4 patients who had biventricular repair were midterm survivors. Overall survival was 56.1% at a median follow-up of 32.0 months. By univariate analysis, patient factors, intact or near-intact atrial septum, and aortic atresia were associated with nonsurvival.

CONCLUSIONS

Hybrid procedure as an alternative to the Norwood procedure offers good midterm survival in patients deemed at high risk for neonatal reconstruction.

Biology and treatment of myeloma

In recent years significant progress has been made in the understanding of multiple myeloma (MM) biology and its treatment. Current strategies for the treatment of MM involve the concept of sequential blocks of therapy given as an induction followed by consolidation and maintenance. In an age characterized by emerging and more powerful laboratory techniques, it is of primary importance to understand the biology of MM and how this biology can guide the development of new treatment strategies. This review focuses on the genetic basis of myeloma, including the most common genetic abnormalities and pathways affected and the effects that these have on MM treatment strategies. MM biology is discussed also in the light of more recent theory of intraclonal heterogeneity.

Abstract 3516: EZH2 overexpression in myeloma patients shortens survival and in-vitro data supports a potential new targeted treatment strategy

Enhancer of zeste homolog 2 (EZH2) induces methylation at histone 3 lysine 27 (H3K27), thought to have a repressive effect on target gene expression. Activating mutations in EZH2 have been shown to drive lymphomas and overexpression linked to poor prognosis in solid tumors. In normal plasma cell development EZH2 expression is downregulated on exit from the germinal centre but in myeloma (MM) expression has been shown to increase with disease progression. Recent work suggests high expression of the H3K36 methyltransferase MMSET sensitizes cells to EZH2 inhibition. We are seeking to further investigate the role of EZH2 in MM.

Data were analyzed from newly diagnosed MM patients in several large clinical trials (Whole-exome sequencing, n = 463 UK Myeloma XI, Affymetrix gene expression array (GEP), n = 259 UK Myeloma IX and n = 1213 UAMS Total Therapy Protocols).

Across the datasets, high expression of EZH2 mRNA shortened patient survival (e.g. UK IX median OS, 29.9 months vs 45.1 months, Log-rank p = 0.005), remaining significant on multivariate analyses and across GEP defined molecular subgroups. Of note, the proliferative subgroup had a higher mean expression of EZH2 (9.56 vs 8.48, t-test p = 5.953e-42) as did high risk patients defined by GEP 70 score (9.61 vs 8.46, t-test p = 1.993e-40) suggesting a link to a more aggressive disease phenotype.

There were no mutations in EZH2. This contrasts with frequent mutations seen in malignancies at earlier stages of B cell development e.g. DLBCL. Of note, 3% of MM patients had a potentially inactivating mutation or deletion in the gene encoding the H3K27 demethylase, KDM6A and significantly shorter OS than those without (% alive 2 yr: Mutated 51% (CI 30-85) vs 80% (CI 77-84), Log-rank p = 0.0498). Such mutations may increase H3K27 methylation, potentially sensitizing patients to EZH2 inhibition.

To study the biological implications of our results we tested the effect of inhibition of EZH2 (EZH2i), using a small molecule EPZ005687, in a panel of MM cell lines representing the epi/genetic diversity of MM. We saw a reduction in total cell number and% viability at 6 days of EZH2i (2-4uM) in 5/8 cell lines with evidence of dose dependent induction of apoptosis. All cell lines (except LP1) had similar levels of EZH2 protein at baseline and the responding cell lines had no unifying epi/genetic anomalies, suggesting response is not specific to either MMSET high or KDM6A mut/del cell lines. 6 days of EZH2i reduced H3K27me2/me3 on Western blotting in all cell lines regardless of viability response, demonstrating the epigenetic activity of the inhibitor. Further evaluation by Chip-seq and GEP is ongoing to identify potential differences, e.g. in focal methylation marks, that may account for differing viability responses.

Our results highlight the prognostic significance of EZH2 in MM and demonstrate excellent in-vitro inhibitor activity suggesting EZH2 as a possible future target for treatment.

Citation Format: Charlotte Pawlyn, Martin F. Kaiser, Caleb K. Stein, Christopher P. Wardell, Veronica Macleod, Rick Edmondson, Bart Barlogie, Brian Walker, Gareth J. Morgan, Faith E. Davies. EZH2 overexpression in myeloma patients shortens survival and in-vitro data supports a potential new targeted treatment strategy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3516. doi:10.1158/1538-7445.AM2015-3516

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.

Assessing myeloma bone disease with whole-body diffusion-weighted imaging: comparison with x-ray skeletal survey by region and relationship with laboratory estimates of disease burden

AIM

To estimate and compare the extent of myeloma bone disease by skeletal region using whole-body diffusion-weighted imaging (WB-DWI) and skeletal survey (SS) and record interobserver agreement, and to investigate differences in imaging assessments of disease extent and apparent diffusion coefficient (ADC) between patients with pathological high versus low disease burden.

MATERIALS AND METHODS

Twenty patients with relapsed myeloma underwent WB-DWI and SS. Lesions were scored by number and size for each skeletal region by two independent observers using WB-DWI and SS. Observer scores, ADC, and ADC-defined volume of tumour-infiltrated marrow were compared between patients with high and low disease burden (assessed by serum paraproteins and marrow biopsy).

RESULTS

Observer scores were higher on WB-DWI than SS in every region (p<0.05) except the skull, with greater interobserver reliability in rating the whole skeleton (WB-DWI: ICC = 0.74, 95% CI: 0.443-0.886; SS: ICC = 0.44, 95% CI: 0.002-0.730) and individual body regions. WB-DWI scores were not significantly higher in patients with high versus low disease burden (observer 1: mean ± SD: 48.8 ± 7, 38.6 ± 14.5, observer 2: mean ± SD: 37.3 ± 13.5, 30.4 ± 15.5; p = 0.06, p = 0.35).

CONCLUSION

WB-DWI demonstrated more lesions than SS in all regions except the skull with greater interobserver agreement. Sensitivity is not a limiting factor when considering WB-DWI in the management pathway of patients with myeloma.

APOBEC family mutational signatures are associated with poor prognosis translocations in multiple myeloma

We have sequenced 463 presenting cases of myeloma entered into the UK Myeloma XI study using whole exome sequencing. Here we identify mutations induced as a consequence of misdirected AID in the partner oncogenes of IGH translocations, which are activating and associated with impaired clinical outcome. An APOBEC mutational signature is seen in 3.8% of cases and is linked to the translocation-mediated deregulation of MAF and MAFB, a known poor prognostic factor. Patients with this signature have an increased mutational load and a poor prognosis. Loss of MAF or MAFB expression results in decreased APOBEC3B and APOBEC4 expression, indicating a transcriptional control mechanism. Kataegis, a further mutational pattern associated with APOBEC deregulation, is seen at the sites of the MYC translocation. The APOBEC mutational signature seen in myeloma is, therefore, associated with poor prognosis primary and secondary translocations and the molecular mechanisms involved in generating them.