A Highly Heterogeneous Mutational Pattern in POEMS Syndrome

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 19-19
Author(s):  
Jia Chen ◽  
Xue-min Gao ◽  
Hao Zhao ◽  
Hao Cai ◽  
Lu Zhang ◽  
...  

Background: POEMS syndrome is a rare plasma cell dyscrasia. Despite the presence of monoclonal protein, POEMS syndrome patients commonly have less than 5% monoclonal plasma cells in the bone marrow. Only one study has reported the genetic and transcriptional features of bone marrow plasma cells, and the underlying role of aberrant plasma cells is not well understood. Herein, in the current study, we aimed to characterize the genetic profile of bone marrow CD138-positive cells from Chinese patients with newly diagnosed POEMS syndrome. Methods: Forty-two patients with newly diagnosed POEMS syndrome based on the International Myeloma Working Group criteria at our institute were included in our study. Twenty milliliters of bone marrow aspirates was obtained and sorted by magnetic microbeads conjugated to monoclonal human anti-CD138 antibodies. The mutational features of these bone marrow plasma cells were analyzed using a two-step strategy. DNA of the bone marrow plasma cells from ten patients was first sequenced by whole exome sequencing to find significantly mutated genes and mutated driver genes, with paired peripheral blood mononuclear cells as a control. Bone marrow plasma cells of an additional thirty-two patients were then analyzed by target region sequencing to validate the mutations. Results: Whole exome sequencing of 10 newly diagnosed patients showed a total of 170 somatic mutations in exonic regions and splicing sites. Three significantly mutated genes-LILRB1 (10%), HEATR9 (20%), and FMNL2 (10%)-and eight mutated known driver genes (MYD88, NFKB2, CHD4, SH2B3, POLE, STAT3, CHD3, CUX1) were identified in five patients. The mutation spectrum of WES revealed C > T/G > A as the most common mutation type, while the mutation signature was not the same as known signatures reported in various cancer types. For significant pathway and gene ontology analysis, 69 genes with possibly pathogenic nonsynonymous mutations were selected. Mutated genes were enriched in pathways including "chromatin organization", "chromatin modifying enzymes", and "apoptosis", and terms such as "cellular anatomical entity", "regulatory region nucleic acid binding" and "centrosome" that are used to describe cellular structure construction. To evaluate the mutation prevalence of genes identified in WES, we performed target region sequencing of 77 candidate genes in 32 other patients. The candidate gene list consisted of significantly mutated genes and known driver genes identified in WES, recurrently mutated genes previously detected in POEMS syndrome, the VEGF gene, and genes of light-chain amyloidosis, multiple myeloma, hematopoietic disease or lymphoid neoplasm in the public databases. As a result, a total of 32 mutated genes were identified in 28 of 32 patients. Genes recurrently mutated in more than three patients included CUX1 (19%), DNAH5 (16%), USH2A (16%), KMT2D (16%), and RYR1 (12%). Driver genes of multiple myeloma (BIRC3, LRP1B, KDM6A, ATM) and eleven genes reported in light-chain amyloidosis were also identified in target region sequencing. Notably, VEGFA mutations were detected in one patient. Conclusions: Heterogeneous genomic profiles of bone marrow plasma cells in POEMS syndrome were revealed in our study. The mutational landscape of POEMS syndrome might share some similarity to that of other plasma cell diseases. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 311-311 ◽  
Author(s):  
Laurie Herviou ◽  
Alboukadel Kassambara ◽  
Stephanie Boireau ◽  
Nicolas Robert ◽  
Guilhem Requirand ◽  
...  

Abstract Multiple Myeloma is a B cell neoplasia characterized by the accumulation of clonal plasma cells within the bone marrow.Epigenetics is characterized by a wide range of changes that are reversible and orchestrate gene expression. Recent studies have shown that epigenetic modifications play a role in multiple myeloma (MM) by silencing various cancer-related genes. We investigated the epigenetic genes differentially expressed between normal bone marrow plasma cells (BMPC ; N=5) and MM plasma cells from patients (N=206). Using SAM (Significance Analysis of Microarrays) analysis, only 12 genes significantly differentially expressed between BMPC and MM cells (ratio > 2 and FDR (false discovery rate) < 5%) were identified, including the EZH2 histone methyltransferase. EZH2, the enzymatic subunit of Polycomb Repressive Complex 2, is a histone methyltransferases able to repress gene expression by catalyzing H3K27me3 histone mark. EZH2 overexpression has been associated with numerous hematological malignancies, including MM. We thus studied EZH2 role in MM physiopathology and drug resistance. EZH2 expression was analyzed in normal bone marrow plasma cells (BMPCs; N=5), primary myeloma cells from newly diagnosed patients (MMCs; N=206) and human myeloma cell lines (HMCLs; N=40) using Affymetrix microarrays. EZH2 gene is significantly overexpressed in MMCs of patients (median 574, range 105 - 4562) compared to normal BMPCs (median = 432; range: 314 - 563) (P < 0.01). The expression is even higher in HMCLs (median 4481, range 581 - 8455) compared to primary MMCs or BMPCs (P < 0.001). High EZH2 expression is associated with a poor prognosis in 3 independent cohorts of newly diagnosed patients (Heidelberg-Montpellier cohort - N=206, UAMS-TT2 cohort - N=345 and UAMS-TT3 cohort - N =158). Furthermore, GSEA analysis of patients with high EZH2 expression highlighted a significant enrichment of genes involved in cell cycle, downregulated in mature plasma cells vs plasmablasts, and EZH2 targets. Specific EZH2 inhibition by EPZ-6438 EZH2 inhibitor induced a significant decrease of global H3K27me3 in all the HMCLs tested (P < 0.01) and inhibited MM cell growth in 5 out of the 6 HMCLs tested. The inhibitory effect of EZH2 inhibitor on MM cell growth appeared at day 6 suggesting that it is mediated by epigenetic reprogramming. To confirm that EZH2 is also required for the survival of primary MMCs from patients, primary MM cells (n = 17 patients) co-cultured with their bone marrow microenvironment and recombinant IL-6 were treated with EPZ-6438. As identified in HMCLs, EZH2 inhibition significantly reduced the median number of viable myeloma cells by 35% (P = 0.004) from a subset of patients (n=9) while the other group (n=8) was resistant. Of interest, EPZ-6438 induced a significant global H3K27me3 decrease in both groups of patient. RNA sequencing of 6 HMCLs treated with EPZ-6438 combined with H3K27me3 ChIP analyses allowed us to create an EZ GEP-based score able to predict HMCLs and primary MM cells sensitivity to EZH2 inhibitors. We also observed a synergy between EPZ-6438 and Lenalidomide, a conventional drug used for MM treatment. More interestingly, pretreatment of myeloma cells with EPZ-6438 significantly re-sensitize drug-resistant MM cells to Lenalidomide. Investigating the effect of EPZ-6438/Lenalidomide combination in MMC, we identified that IKZF1, IRF4 and MYC protein levels were significantly more inhibited by the combination treatment (65.5%, 63.9% and 14.8% respectively) compared with Lenalidomide (51.5%, 43% and 2.2%) or EPZ-6438 (45.2%, 38.7% and 6.2%) alone. Clinical trials are ongoing with EZH2 inhibitors in lymphoma and could be promising for a subgroup of MM patients in combination with IMiDs. Furthermore, the EZ score enables identification of MM patients with an adverse prognosis and who could benefit from treatment with EZH2 inhibitors. Disclosures Goldschmidt: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Hose:EngMab: Research Funding; Takeda: Other: Travel grant; Sanofi: Research Funding.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3369-3369 ◽  
Author(s):  
Veronica Gonzalez de la Calle ◽  
Ramon Garcia-Sanz ◽  
Eduardo Sobejano ◽  
Enrique M. Ocio ◽  
Noemi Puig ◽  
...  

Abstract BACKGROUND Smoldering multiple myeloma (SMM) is a plasma cell proliferative disorder with no related organ or tissue impairment. It is associated with a risk of progression to symptomatic multiple myeloma (MM) of approximately 10% per year. Several prognostic factors for the progression to active disease have been identified, such as those defined by the Mayo Clinic including the proportion of bone marrow plasma cells, the serum monoclonal protein level at diagnosis and the serum immunoglobulin free light chain ratio (FLC); or those defined by the Spanish Group including the proportion of bone marrow aberrant plasma cells assessed by flow cytometry plus immunoparesis. The presence of Bence Jones (BJ) proteinuria is a myeloma feature associated with renal function and tumor burden as well. There is lack of evidence about the role of BJ proteinuria in SMM as predictor marker of progression to symptomatic disease. AIMS The goal of the present study was to investigate the role of the presence of Bence Jones proteinuria at diagnosis in SMM as predictor of progression to symptomatic disease. METHODS We reviewed 147 medical records of SMM patients from area of Castilla y León (Spain), diagnosed between 1983 and 2013, according to the criteria of the International Myeloma Working Group. The primary endpoint was time to progression to active multiple myeloma (hypercalcemia, renal insufficiency, anemia or bone lesions). RESULTS 147 patients with SMM were included in the analysis. The median age at diagnosis was 69 years-old (range: 34-90).The serum M-protein at diagnosis ranged from 1 to 26 g/l (median,25). 70% of SMM were Ig G subtype. The proportion of bone marrow plasma cells ranged from 1% to 55% (median, 14). In 64 % of SMM, the percentage of aberrant plasma cells assessed by flow cytometry was superior to 95% and 51% had immunoparesis. Bence Jones proteinuria was detected at diagnosis in 40 patients (27%) and the average amount of urinary monoclonal light chain was 236 mg per 24h. Of those patients, 58% had a monoclonal kappa light chain. The FLC ratio was assessed in 18 patients and it was abnormal (<0.26 or >1.65) in 83% of them. The median level of involved Immunoglobulin was 88.5 mg/l (range, 13-1200) and the median ratio of involved to uninvolved was 10.8 (range, 2.2-3360). In 4 patients, FLC ratio was greater than 100. At a median follow-up of 54 months, progression to active disease occurred in 49%. Anemia was the most common CRAB feature at the time of progression. Median time to progression (TTP) to symptomatic disease in the whole series was 63 months. SMM with BJ proteinuria had a significantly shorter median TTP to active disease as compared with patients without BJ proteinuria (21.7 months vs 82.9 months ;HR: 2.44, IC 95%: 1.48-4.02; p<0.001). The progression risk at 2 years in the BJ group of SMM was 53%. Multivariate analysis selected BJ proteinuria at diagnosis as an independent variable for progression to symptomatic MM (HR: 2.47, IC 95%: 1.32-4.63; P=0.005). Using this independent variable, we identified 4 risk categories according to amount of urinary monoclonal light chain: 0 mg per 24h; 1-250 mg/24h; 251-500 mg/24h ; or more than 500 mg/24h, with a median TTP of 83, 37, 16 and 7 months, respectively; p <0.001. CONCLUSIONS The presence of Bence Jones proteinuria at diagnosis in SMM patients is associated with significantly higher risk of progression to active MM (53% risk of progression at 2 years). Moreover, the presence of more than 500 mg of BJ proteinuria can be considered as a marker for the identification of ultra high risk SMM. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3396-3396 ◽  
Author(s):  
Robert Kyle ◽  
Ellen Remstein ◽  
Terry Therneau ◽  
Angela Dispenzieri ◽  
Paul Kurtin ◽  
...  

Abstract Smoldering multiple myeloma (SMM) is characterized by a serum M protein ≥ 3g/dL and/or 10% or more of plasma cells in the bone marrow. However, the definition is not standardized, and it is not known whether both serum M protein levels and bone marrow plasma cell counts are necessary for diagnosis or if one parameter is sufficient. We reviewed the medical records and bone marrows of all patients from Mayo Clinic seen within 30 days of recognition of an IgG or IgA M protein ≥ 3g/dL or a bone marrow containing ≥ 10% plasma cells from 1970 to 1995. This allows for a minimum potential follow-up of 10 years. Patients with end-organ damage at baseline from plasma cell proliferation, including active multiple myeloma (MM) and primary amyloidosis (AL) and those who had received chemotherapy were excluded. A differential of the bone marrow aspirate coupled with the bone marrow biopsy morphology and immunohistochemistry using antibodies directed against CD138, MUM-1 and Cyclin D1 were evaluated in every case in order to estimate the plasma cell content. In all, 301 patients fulfilled either of the criteria for SMM. Their median age was 64 years and only 3% were less than 40 years of age; 60% were male. The median hemoglobin value was 12.9 g/dL; 7% were less than 10 g/dL, but the anemia was unrelated to plasma cell proliferation. IgG accounted for 75%, IgA 22%, and biclonal proteins were found in 3%. The serum light-chain was κ in 67% and λ in 33%. The median serum M spike was 2.9 g/dL; 11% were at least 4.0 g/dL. Uninvolved serum immunoglobulins were reduced in 81%; only 1 immunoglobulin was reduced in 31% and both were decreased in 50%. The urine contained a monoclonal κ protein in 36% and λ in 18% and 46% were negative. The median size of the urine M spike was 0.04 g/24h; only 5 (3%) were &gt; 1 g/24h. The median bone marrow plasma cell content was 15 – 19%; 10% had less than 10% plasma cells, while 10% had at least 50% plasma cells in the bone marrow. Cyclin D-1 was expressed in 17%. Patients were categorized into 3 groups: Group 1, serum M protein ≥ 3g/dL and bone marrow containing ≥ 10% plasma cells (n= 113, 38%); Group 2, bone marrow plasma cells ≥ 10% but serum M protein &lt; 3g/dL (n= 158, 52%); Group 3, serum M protein ≥ 3g/dL but bone marrow plasma cells &lt; 10% (n= 30, 10%). During 2,204 cumulative years of follow-up 85% died (median follow-up of those still living 10.8 years), 155 (51%) developed MM, while 7 (2%) developed AL. The overall rate of progression at 10 years was 62%; median time to progression was 5.5 yrs. The median time to progression was 2.4, 9.2, and 19 years in groups 1, 2, and 3 respectively; correspondingly at 10 years, progression occurred in 76%, 59%, and 32% respectively. Significant risk factors for progression with univariate analysis were serum M spike ≥ 4g/dL (p &lt; 0.001), presence of IgA (p = 0.003), presence of urine light chain (p = 0.006), presence of λ urinary light chain (p = 0.002), bone marrow plasma cells ≥ 20% (p &lt; 0.001) and reduction of uninvolved immunoglobulins (p &lt; 0.001). The hemoglobin value, gender, serum albumin, and expression of cyclin D-1 were not of prognostic importance. On multivariate analysis, the percentage of bone marrow plasma cells was the only significant factor predicting progression to MM or AL.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5110-5110
Author(s):  
Adam D Cohen ◽  
Ping Lu ◽  
Sacha Gnjatic ◽  
James Hoffman ◽  
Erika Ritter ◽  
...  

Abstract The cancer-testis antigens (CTA) are highly immunogenic antigens expressed in various tumors but not in normal tissues (except during gametogenesis), making them an attractive target for cancer immunotherapy. Expression of CTAs such as MAGE-A3, MAGE-C1 (CT7), MAGE-C2 (CT10), NY-ESO1 and the SSX antigens has been previously reported in multiple myeloma (MM). To date, however, these reports have included a heterogeneous group of newly diagnosed and relapsed/refractory patients, all in different stages of treatment. Therefore, the extent and prognostic significance of CTA expression, and of de novo immune responses against CTA in newly-diagnosed MM patients are not known. We now report on both CTA expression and antibody responses in MM patients at diagnosis and on their prognostic significance. From 8/00-11/04, we treated 67 newly-diagnosed, symptomatic patients with a thalidomide, doxorubicin, and dexamethasone-based induction regimen. (Brit J Haematol2006;132:155). Median age was 58; 54% were ISS stage I, 28% ISS II, and 18% ISS III. Nine of 63 tested (14%) had deletion 13q by FISH, while 24% had soft tissue involvement by MM. Responses to induction therapy included 10 (15%) CR, 16 (24%) VGPR, 26 (39%) PR, 6 (8%) stable or progressive disease, and 9 (13%) inevaluable. Post-induction 54 underwent autoSCT and 9 also underwent alloSCT.. Median overall survival (OS) has not been reached with 61% alive at median follow up of 65 months. Cryopreserved pre-treatment bone marrow plasma cells were used to assess CTA expression by RT-PCR. Pre- and post-treatment sera were used to assess antibody (Ab) responses against CTA proteins by ELISA. Fifty-two patients had sufficient RNA for PCR, and 46 had baseline serum for ELISA. OS of these groups did not differ significantly from the entire cohort. At least 1 CTA was expressed in 77% of cases, including MAGE-A3 (52%), SSX1 (40%), CT7 (29%), CT10 (25%), NY-ESO1 (21%), and SSX5 (17%). Three or more CTA were expressed in 29% of cases. Individually MAGE-A3 or NY-ESO1 expression at diagnosis conferred a poorer prognosis (MAGE-A3: median OS 66 mos. vs. not reached, p=0.02 by log-rank; NY-ESO1: median OS 65 mos. vs. not reached, p=0.09). These poorer outcomes were independent of ISS stage, presence of del 13q, or response to induction therapy. No other CTA was associated with an OS difference, nor was the total number of CTA expressed prognostically significant. Baseline Ab responses, all at titers &gt; 1:1600, were noted to NY-ESO1 in 6/46 (13%) patients, 5 of whom also had Ab to the NY-ESO1 homologue LAGE-1. Ab responses were also noted to CT7 (n=2), CT10 (n=1) and SSX4 (n=1). No Ab responses were noted to MAGE-A3. The effect of induction therapy on antibody titers was inconsistent, with increases, decreases, and no changes seen. Interestingly, 2 of the 6 NY-ESO1 Ab+ patients had no NY-ESO1 expression in bone marrow plasma cells. Both, however, had extensive soft tissue (ST) plasmacytomas, suggesting another source of NY-ESO1 antigen. Presence of NY-ESO1 Ab correlated significantly with baseline ST involvement, with 67% of Ab+ patients having ST disease compared with 20% of Ab− patients (p=0.05). NY-ESO1 Ab+ patients also had significantly poorer OS (med 21 mos. vs. not reached, p=0.009), independent of other prognostic factors. In sum, CTA expression is frequent in newly diagnosed MM patients, and expression of MAGE-A3 or NY-ESO1 is associated with worse long-term survival. Spontaneous antibody responses against NY-ESO1 are seen in untreated patients, and are associated with ST involvement and poorer survival. Further exploration of biologic differences between CTA+ and CTA-MM, as well as immunotherapeutic strategies which target these antigens, are warranted.


2016 ◽  
Vol 44 ◽  
pp. 32-39 ◽  
Author(s):  
Wilson I. Gonsalves ◽  
Michael M. Timm ◽  
S.Vincent Rajkumar ◽  
William G. Morice ◽  
Angela Dispenzieri ◽  
...  

HemaSphere ◽  
2019 ◽  
Vol 3 (S1) ◽  
pp. 647
Author(s):  
G. Rivoli ◽  
N. Bisso ◽  
A. Cagnetta ◽  
S. Aquino ◽  
M. Bruzzone ◽  
...  

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1487-1487 ◽  
Author(s):  
Angela Dispenzieri ◽  
Robert A. Kyle ◽  
Jerry A. Katzmann ◽  
Dirk Larson ◽  
Joanne Benson ◽  
...  

Abstract Background: Smoldering multiple myeloma (SMM) is an asymptomatic plasma cell proliferative disorder with a high risk of progression to symptomatic multiple myeloma. Identification of risk factors that predict progression of SMM to symptomatic MM could identify higher risk patients who might benefit from chemoprevention or more intensive surveillance. We hypothesized that increased monoclonal free kappa or lambda immunoglobulin light chains in smoldering myeloma (SMM), as detected by the serum free light chain (FLC) assay, indicates an increased the risk of progression to active myeloma. Methods: Of 276 pathologically confirmed SMM patients seen at the Mayo Clinic from 1970 to 1995, baseline serum samples obtained within 30 days of diagnosis were available in 273. Results: At a median follow-up of surviving patients of 12.4 years, transformation to active disease has occurred in 161 (59%) patients. An abnormal FLC ratio was present at baseline in 90% of patients. The best break-point for predicting risk of progression was a FLC ratio less than or equal to 0.125 or greater than or equal to 8 (hazard ratio, 2.3; 95% CI, 1.6–3.2) [Figure 1]. The extent of abnormality of FLC ratio was independent of SMM risk categories defined by number of plasma cells in the bone marrow and size of serum M-proteins (bone marrow plasma cells ≥ 10% and serum M protein ≥ 3 g/dL; bone marrow plasma cells ≥ 10% but serum M protein &lt; 3 g/dL; and serum M protein ≥ 3 g/dL but bone marrow plasma cells &lt; 10%). Incorporating the FLC ratio into the risk model, the division of patients into high-, intermediate-, and low-risk groups is 28, 42, and 30% with 5 year progression rates of 76, 51, and 25%, respectively [Figure 2]. Conclusions: The serum immunoglobulin FLC ratio is an important additional determinant of clinical outcome in patients with SMM. Figure Figure Figure Figure


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1757-1757
Author(s):  
Chen Wang ◽  
Qian-qian Cai ◽  
Xin-xin Cao ◽  
Dao-bin Zhou ◽  
Jian Li

Abstract Background : POEMS syndrome is a rare paraneoplastic disorder, characterized by polyneuropathy, organomegaly, osteosclerosis and extravascular volume overload, due to an underlying plasma cell dyscrasia. Vascular endothelial growth factor (VEGF), a potent angiogenic cytokine that can increase vascular permeability, plays a critical role in its pathogenesis. Despite extensive VEGF studies concerning its role in disease diagnosis, monitoring and response assessment, little is known about its cellular source and mechanisms governing the production of VEGF in POEMS patients. Methods and Materials : Patients with POEMS syndrome, 62 newly diagnosed and 46 of them after lenalidomide-dexamethasone (LenDex) treatment, admitted to Peking Union Medical College Hospital between February 2014 and April 2015, were included in the current study. Clinical information, serum and bone marrow samples were collected with the Institutional approval. Serum levels of VEGF were measured by ELISA. VEGF levels in bone marrow plasma cells were quantified via real-time quantitative PCR and multiparameter flow cytometry, respectively. In addition, the phenotype, clonality and intracellular interleukin-6 (IL-6) expression of bone marrow plasma cells were also analyzed by flow cytometry. Furthermore, immunohistochemical staining was performed to study the plasma cell distribution, clonality and expression of VEGF, IL-6 and hypoxia-inducible factor-1α (HIF-1α) in bone marrow biopsies. Statistical analyses were conducted using SPSS 22, and a p < 0.05 was considered as significant. Results : Serum levels of VEGF were dramatically elevated in patients with newly diagnosed POEMS syndrome (median 5958 pg/mL), significantly higher than both disease and healthy controls (p < 0.001), and can be used as a diagnostic marker (area under curve 0.988, p < 0.001). A cut-off value of 2000 pg/mL had a specificity of 97.7% with a sensitivity of 91.9% in support of the diagnosis. After treatment, VEGF levels decreased gradually (6-cycle after LenDex, median 1184 pg/mL, p < 0.001; 12-cycle after LenDex, median 832 pg/mL, p < 0.001). Bone marrow plasma cells showed remarkable VEGF expression, validated in both mRNA and protein levels, which also decreased in response to LenDex therapy. More importantly, a statistically linear correlation was observed between serum and bone marrow plasma cell VEGF levels (newly diagnosed patients, rho = 0.33, p = 0.01; post-therapeutic patients, rho = 0.53, p < 0.001), supporting that bone marrow plasma cells were the source of circulating VEGF. Intriguingly, immunophenotying revealed that bone marrow plasma cells were polyclonal in most newly diagnosed cases. Monoclonal population, co-existing with polyclonal plasma cells, was observed only in 11 patients (18%). Further analyses showed that the relative amounts of these two populations were similar (41% vs. 59%) and they also had comparable intracellular VEGF expression (mean fluorescent intensity, 2009 vs. 2367, p = 0.594). However, monoclonal plasma cells had significantly higher intracellular IL-6 expression (mean fluorescent intensity, 1635 vs. 865, p = 0.006). In 46 newly diagnosed cases with bone marrow biopsies available, immunohistochemical staining was performed, and plasma cells were typically distributed in a scattered manner, with focal aggregates observed in 21 cases (46%). Intracellular κ and λ light chain staining demonstrated that the background scattered plasma cells were polyclonal, while both monoclonal and polyclonal fractions were observed in the focal area, which showed similar nuclear and intracellular staining of HIF-1α and VEGF, respectively. In contrast, IL-6 was mainly expressed in λ-restricted plasma cells. Conclusion : Bone marrow plasma cells are the potential source of VEGF production in patients with POEMS syndrome. Monoclonal plasma cells, aggregates focally in the bone marrow, may secret IL-6 to stimulate polyclonal plasma cells proliferation, and consequent VEGF production in a paracrine circuit. Disclosures Off Label Use: Lenalidomide for POEMS syndrome.


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