scholarly journals CIC-Mutation As a Potential Molecular Mechanism of Acquired Resistance to Combined BRAF/MEK Inhibition in CNS Multiple Myeloma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3181-3181 ◽  
Author(s):  
Matteo Claudio Da Via' ◽  
Antonio Giovanni Solimando ◽  
Andoni Garitano-Trojaola ◽  
Santiago Barrio ◽  
Nadine Rodhes ◽  
...  

Abstract Central nervous system (CNS) involvement is an extremely rare extramedullary multiple myeloma (MM) manifestation, diagnosed in less than 1% of patients. It is considered an ultimate high-risk feature, associated with unfavorable cytogenetics, and, even with intense treatment applied, survival is short, reaching less than 12 months in most cases. In June 2017 an 81 years old male with a κ light chain MM was referred to our institution for an isolated CNS MM relapse. His cerebrospinal fluid (CSF) demonstrated a high load of clonal plasma cells, however, the patient's bone marrow infiltration was very little with a percentage of plasma cells less than 5%. Imaging, including gold standard MRI and experimental 11C-methionine PET scan, was performed, and high metabolic activity was detected supra- and infratentorially as well as in the right femur and the clivus. Following CD138+ cell purification we analyzed the specimen with M3P (v3.0) a disease specific in-house customized, next generation targeted sequencing panel for MM (Ion torrent platform). This includes most commonly mutated MM genes, actionable drug targets and drug resistance associated genes. The average sequencing depth increased 700X and spatial MM heterogeneity was detected, as the CFS cells harbored a clonal BRAFV600E mutation, absent in the bone marrow. Initial intrathecal and systemic chemotherapy with Cytarabine and Thiotepa was intolerable, thus the patient underwent a combined target inhibition with Dabrafenib/Trametinib, well known specific BRAF and a MEK 1/2 inhibitors. The patient displayed a rapid complete response (Figure. 1A), however, disease relapse occurred after three months of therapy. We obtained a sequential CFS sample and Whole Exome Sequencing (Illumina platform) was applied to pre and post therapy CFS sampling. Exome sequencing of the two time points performed an average sequencing depth of 115X; a total number of 97 non-silent coding variants (missense, nonsense, indels, splice) with an allele frequency higher than 5% were detected. In detail, 19 point mutations were acquired at relapse, including a subclonal missense mutation in CIC (p.A984P, VRF 17%), recently identified as a candidate gene contributing to MEK/BRAF resistance development. Next, we established a CIC knock-down model electroporating a specific anti-CIC siRNA into U266 MM cell line. We cultured the silenced and not-silenced cells with Trametinib and Dabrafenib, either as single agents, or in combination. As expected, we observed resistance induction to the combination of the two drugs (Row Factor 85.94%; P<0.0001, Two-way ANOVA) suggesting a critical role for this patient derived mutation for his MEK/BRAF resistance development (Figure 1C, D). In order to better clarify the landscape pathway related to CIC we analyzed expression data from 647 patients enrolled in the MMRF CoMMpass trial. Remarkably, we found a significant down-regulation of ERF and ETV6 (t-test -9.95, -9.93, P <0.001, respectively), two well characterized tumor suppressor genes correlated with the re-activation of the RAS downstream pathway (Figure 1B). This is the first report giving evidence for a potential role of point mutations in CIC as a resistance mechanism to targeted MEK/BRAF inhibition in BRAF mutated MM. The performed pathway analysis significantly extends the insights of the resistance mechanisms highlighted. Our results foster a statistically powered study to corroborate the clinical relevance. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2917-2917
Author(s):  
Jennifer Li ◽  
Andrew Leu ◽  
Mingjie Li ◽  
Ethan D Hobel ◽  
Kevin Delijani ◽  
...  

Abstract Abstract 2917 The inhibitory Fc receptor, Fc γRIIb, is expressed on plasma cells, controls their persistence in the bone marrow (BM) and their ability to produce serum Ig. Activation of Fc γRIIb leads to the phosphorylation of ITIM and recruitment of SH2-containing inositol 5'-phosphatase (SHIP) in plasma cells. Immunoreceptor tyrosine-based activation motif (ITAM) and ITIM provide the basis for two opposing signaling modules that duel for control of plasma cell activation. Fc γRIIb-mediated SHIP phosphorylation activates downstream ITAM or ITIM signaling. To determine whether multiple myeloma (MM) cells express Fc γRIIb, we performed immunohistochemical staining on bone marrow mononuclear cells from MM patients and controls. We found that not only CD20+ B cells expressed Fc γRIIb but more importantly CD138+ cells from MM patients also showed expression of this receptor. Next, we examined whether Fc γRIIb was present and expressed in CD138+ primary MM cells purified from fresh MM BM and the MM cell lines MM1s, RPMI8226, and U266 using PCR and RT-PCR on DNA and mRNA, respectively. We focused on the transmembrane domain of the Fc γRIIb gene with four primers from different parts of this domain since this portion plays a critical role in this receptor's function. The MM cell lines expressed different amounts of Fc γRIIb. Notably, we found that 17% (5/30) of MM patients showed absence of Fc γRIIb both using RT-PCR for mRNA and PCR for DNA. Moreover, use of these same primers on nonmalignant PBMCs from the MM patients also showed absence of this gene in the same five patients. As a result of these findings, we are currently sequencing Fc γRIIb in MM patients to determine if additional patients show mutational changes that affect the function of this receptor. We also further determined SHIP-1 phosphorylation using Western blot analysis since this protein mediates downstream signaling of Fc γRIIb. Following stimulation with Fc complexes, phosphorylation of SHIP-1 was markedly reduced in MM tumor cells compared to normal CD20+ B cells. Interestingly, the patients with missing Fc γRIIb expressed higher levels of SHIP-1 gene expression compared to patients with normal Fc γRIIb expression. We investigated the IgG-binding ability of MM patients (n=33) and normal donors (n=33) to Fc γRIIb. Each serum sample was incubated with cells from MHC1, a cell line that specifically expresses Fc γRIIb but not Fc γRI and Fc γRIIa. The results showed MM patients' serum IgG have much lower Fc γRIIb-binding ability than normal human IgG (P<0.05) by using both flow cytometric and immunofluorescence assays. Our findings suggest that the monoclonal protein produced by MM patients has a very low Fc γRIIb-binding ability and is incapable of signaling through the inhibitory ITIM pathway. Germline loss of Fc γRIIb in MM patients with variation in its expression level and its downstream signaling molecule SHIP and its phosphorylation as well as the inability of MM IgG to bind cells containing this receptor is a potential new mechanism that contributes to the uncontrolled growth of MM. Disclosures: Berenson: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Millennium Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding, Speakers Bureau; Onyx Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Medtronic: Consultancy, Honoraria, Research Funding, Speakers Bureau; Merck: Research Funding; Genentech: Research Funding.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 5063-5063
Author(s):  
Hossein Mossafa ◽  
Sabine Defasque ◽  
Christine Fourcade ◽  
JeanPierre Hurst ◽  
Bertrand Joly

Abstract Abstract 5063 Introduction, We describe the simultaneous presentation of multiple myeloma (MM) and yeloproliferative disorders (MPD) or lymphoid diseases (LD) at diagnosis. Therapy-related myelodysplasia (tMDS) occurring during the course of MM is generally believed as a result from hematopoietic stem cell-toxic therapies, such as ionizing radiation and alkylating agent-based chemotherapies (melphalan, nitrosoureas).Patients and methods, We study a total of 342 patients (151 F, 191 M; median age 68.1 years; range 42 to 93 Years), diagnosed with MM based on the International Staging System. The basis for inclusion of patients in this study was with previous untreated MM ones. The study was performed in accordance with the declaration of Helsinki. To determine whether chemotherapies for MM factors play the critical role in the development of secondary disease, simultaneously two different cultures were processed, an unstimulated 96 hours culture (U96HC) on whole BM(WBM), a short-time 24 hours culture (ST24HC) after CD138+ plasma cells (PCs) depleted on negative fraction (CD138- cells) of BM and the FISH was investigated on purified CD138+.All samples were enriched in PCs by the Automated Magnetic Cell Sorter (Miltenyi technology)proceeded with anti-CD138 specific antibodies applied. The CD138+ PCs and the CD138- cells were collected in different tubes. The CD138− cells were used for a ST24HC. FISH was performed on the purified CD138+, PCs with a recommended FISH panel (MM International Working Group). Screening was performed systematically for the following unbalanced alterations and reciprocal rearrangements: del(13)(q14)(D13S25), del(17)(p13)(TP53),+3(D3Z), +9(D9Z1), +15(D15Z14), t(4;14)(p16;q32)/IGH-FGFR3, t(11;14)(q13;q32)/IGH-CCND1 (Abbott).After observing the results of U96HC on whole BM (CD138+ and CD138− cells), ST24HC (CD138− cells) and FISH for each patient, two clone cytogenetically were distinct and unrelated chromosomal abnormalities were found in 40 (11.7%) of the 342 MM patients (6 F, 34 M; median age 74 years; range 42 to 87 Years) 34 had a MPD and 6 had a LD. A second immunophenotyping analysis confirmed the presence of those LD/MM simultaneous haematological malignancy. In the cases of the patients with MM/ MPD, the frequency of cytogenetic abnormality unrelated to the myeloma clone was respectively; the 20q deletion, detected for 13 the 34 patients, the 20q- is a sole abnormality for 12 cases and associated with a complex caryotype in 1 case. The trisomy of chromosome +8 was observed in 7 cases, the del(7q) or monosomy 7 in 5 cases, loss of gonosome Y in 4 cases, del(11) for 2 cases, translocation t(9;22) in one case, 5q abnormality in one case and trisomy 9 with JAK2 V617F mutation in one case. For the patients with MM/LD, 5 patients had a trisomy +12 and or trisomy +18 like sole abnormality or associated with others cytogenetics abnormalities and one patient had 6q deletion. Discussion, Whereas in the literature the most common cytogenetic abnormalities typifying MPD after alkylator-based therapy include partial or complete deletions of chromosomes 5, 7, and 20 as well as trisomy 8. In our study we observed those abnormalities with the same frequency for the patients had simultaneous MPD associated in untreated MM at diagnosis. Six patients had simultaneous LD and MM. The marginal zone lymphoma was confirmed for 3 patients. The CC observed a trisomy +12 for those three patients associated with +18 and +19 for 2 cases and del(13) and trisomy 3 for one among them. We demonstrated in untreated MM patients the coexistence of MM and MPD or LD at diagnosis with MPD-type or LD-type chromosome abnormalities within MM signature karyotype. We hence recommend that CC studies, 96 hours WBM, 24 hours on negative fraction CD138− cells and FISH on purified CD138+ PCs, the three should be an integral part of the evaluation of patients with MM at diagnosis into clinical trials using HDT is warranted to determine whether patients who are predisposed to developing tMDS/sAML, they can be identified prospectively. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3985-3985
Author(s):  
Francesca Fontana ◽  
Josè Manuel garcia Manteiga ◽  
Magda Marcatti ◽  
Francesca Lorentino ◽  
Giovanni Tonon ◽  
...  

Abstract Abstract 3985 Multiple myeloma is a malignancy of plasma cells, which grows at multiple foci in the bone marrow, secretes monoclonal immunoglobulins, and typically induces skeletal destruction, hypercalcemia, anemia, and renal failure. Although it remains an incurable cancer, novel therapeutic regimens have improved overall survival in the last decade. Multiple myeloma originates from post germinal center, terminally differentiated B lymphocytes through a multi-step process involving early and late genetic changes. Multiple myeloma is preceded by monoclonal gammopathy of undetermined significance (MGUS), a frequent age-progressive premalignant expansion of bone marrow plasma cells that behave benignly despite the presence of most myeloma-specific genetic abnormalities. Indeed, development and progression of multiple myeloma are believed to rely on vicious interactions with the bone marrow environment, offering a paradigm to investigate the bone-cancer relationship. In particular, bone and stromal cells are known to be diverted by cancer cells through altered cytokine circuitry. The resulting enhanced osteoclastogenesis and neoangiogenesis, and reduced osteoblast differentiation and activity sustain cancer cell survival, proliferation, migration and chemoresistance. Such crucial interactions, however, have only partially been elucidated in their complexity, dynamics and exact role in disease evolution. A better knowledge of this interplay, still elusive, could help identify prognostic markers, pathomechanisms, and therapeutic targets for future validation. Aiming to achieve an unbiased, comprehensive assessment of the extracellular milieu during multiple myeloma genesis and progression, we performed a metabolomic analysis of patient-derived peripheral and bone marrow plasma by ultra high performance liquid and gas chromatography followed by mass spectrometry. By feature transformation-based multivariate analyses, metabolic profiling of both peripheral and bone marrow plasma successfully discriminated active disease from control conditions (health, MGUS or remission). Moreover, both central and peripheral metabolic scores significantly correlated with bone marrow plasma cell counts. Significant changes in the peripheral metabolome were found to be associated with abnormal renal function in the subset of myeloma patients. Noteworthy, however, renal dysfunction-associated features failed to independently predict disease load, while non-overlapping disease vs. control analyses consistently identified a number of metabolites associated with disease. Among these, increased levels of the C3f-derived peptide, HWESASLL, and loss of circulating lysophosphocholines emerged as hallmarks of active disease. In vitro tests on myeloma cell lines and primary patient-derived cells revealed a previously unsuspected direct trophic role exerted by lysophosphocholines on malignant plasma cells. Altogether, our data demonstrate that metabolomics is a powerful approach suitable for studying the complex interactions of multiple myeloma with the bone marrow environment and general metabolism. This novel strategy holds potential to identify unanticipated markers and pathways involved in development and progression of multiple myeloma. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 5009-5009
Author(s):  
Nassim Nabbout ◽  
Mohamad El Hawari ◽  
Thomas K. Schulz

Abstract Abstract 5009 Multiple myeloma is a neoplastic proliferation of monoclonal plasma cells that can result in osteolytic bone lesions, hypercalcemia, renal impairment, bone marrow failure, and the production of monoclonal gammopathy. The gastrointestinal tract is rarely involved in myeloma. GI polyposis is a rare manifestation of extra-medullary disease in multiple myeloma. Such cases usually present as gastrointestinal hemorrhage or intestinal obstruction. A 53-year-old African American male recently diagnosed with multiple myeloma presented with three-day history of rectal bleed and fatigue. EGD showed multiple raised, polypoid, rounded lesions with a superficial central ulceration in the stomach. Colonoscopy showed similar lesions in the ascending and transverse areas of the colon that ranged in size from 5 to 16 mm in diameter. Biopsies showed that these polyps were made of plasma cells. A bone marrow biopsy showed diffuse involvement (greater than 90%) of bone marrow with multiple myeloma with anaplastic features. The patient was started on bortezomib at diagnosis, however, he passed away a few weeks later. This type of metastatic disease has been described in isolated case reports in the literature, while solitary GI plasmacytoma has been reported more frequently. In rare cases, multiple myeloma can involve the GI tract which may lead to bleed or obstruction. This involvement is likely a marker of aggressivity. This example of extra-medullary disease in myeloma is an uncommon variant with features of poor prognosis and dedifferentiation. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5316-5316
Author(s):  
Andrei Garifullin ◽  
Irina Martynkevich ◽  
Sergei Voloshin ◽  
Alexei Kuvshinov ◽  
Ludmila Martynenko ◽  
...  

Abstract Background. Genetic anomalies (GA) are primary link of pathogenesis in MM. GA lead to formation of clonal plasma cells, which has different phenotype. Aim. To estimate the incidence of GA and their correlation with clonal plasma cells' phenotype in patients with ND MM. Methods. We analysed 22 patients with ND MM (median age 57 years, range 38-80; male/female - 1:1.75). Cytogenetic analysis was performed on bone marrow samples using standard GTG-method. Metaphase FISH analysis was performed according to the manufacturer's protocol using DNA probes: LSI 13(RB1)13q14, IGH/CCND1, IGH/FGFR3, LSI TP53 (17q13.1). 8-color immunophenotypic by flow cytometry using antibody to CD45, CD38, CD138, CD56, CD19, CD20, CD27 and CD117 antigenes. Results. Translocation t(11;14) was detected in 3/14 (21.4%) patients, del(13q) - 2/14 (14.3%), t(11;14) - 3/14 (21.4%), hypodyploidy - 1/20 (5%), del(17р) - 0% patients. Clonal plasma cells' phenotype CD38+CD138+CD45- was detected in 100%. Expression CD56+ was revealed in 11/22 (50%) patients, CD19+ in 9/22 (40.9%), CD117+ in 5/22 (22.7%), CD20+ in 1/22 (4.5%), CD27+ in 1/22 (4.5%). The frequency of GA didn't depend on clonal plasma cells' phenotype and was 27.3%(3/11) in CD56+ phenotype, 23.8%(5/21) - CD20-, 23.8%(5/21) - CD27-, 23.5%(4/17) - CD117-, 23%(3/13) - CD19-, 22.2%(2/9) - CD19+, 20%(1/5) - CD117+, 18.2%(2/11) - CD56-, 0%(0/1) - CD20+, 0%(0/1) - in CD27+ phenotype. Patients of standard risk group according to mSMART 2.0 with GA had CD19-negative plasma cells' phenotype vs. CD19-positive phenotype in patients of intermediate and high-risk groups (p<0.05). 3-years overall survival in standard risk group with CD19- phenotype was 92,3%, CD19+ - 77,7% (p>0.05). Conclusion . Identification of GA, which has adverse forecast, correlates with CD19+ plasma cells phenotype. The combined definition of plasma cells phenotype and GA can improve the system of risk stratification in MM. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
1991 ◽  
Vol 77 (12) ◽  
pp. 2688-2693 ◽  
Author(s):  
F Caligaris-Cappio ◽  
L Bergui ◽  
MG Gregoretti ◽  
G Gaidano ◽  
M Gaboli ◽  
...  

We have verified the hypothesis that multiple myeloma (MM) may be disseminated by circulating clonogenic cells that selectively home to the bone marrow (BM) to receive the signal(s) leading to proliferation, terminal differentiation, and production of the osteoclast activating factors. Long-term cultures of stromal cells have been developed from the BM of nine patients with MM. These cells were mostly fibroblast- like elements, interspersed with a proportion of scattered macrophages and rare osteoclasts. BM stromal cells were CD54+, produced high levels of interleukin-6 (IL-6) and measurable amounts of IL-1 beta, and were used as feeder layers for autologous peripheral blood mononuclear cells (PBMC). After 3 weeks of cocultures, monoclonal B lymphocytes and plasma cells, derived from PBMC, developed and the number of osteoclasts significantly increased. Both populations grew tightly adherent to the stromal cell layer and their expansion was matched by a sharp increase of IL-6 and by the appearance of IL-3 in the culture supernatant. These data attribute to BM stromal cells a critical role in supporting the growth of B lymphocytes, plasma cells, and osteoclasts and the in vivo dissemination of MM.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. SCI-12-SCI-12
Author(s):  
Karin Vanderkerken ◽  
Kim De Veirman ◽  
Ken Maes ◽  
Eline Menu ◽  
Elke De Bruyne

Apoptosis plays a key role, not only in normal homeostasis but also in protection against genomic instability. Protection against apoptosis is a hallmark of cancer and is mainly regulated by the overexpression of anti-apoptotic proteins such as Bcl-2, Bcl-Xl or Mcl-1. This results in increased survival of the tumor cells and resistance to therapy. This presentation will focus on MCL-1 (myeloid cell leukemia 1), its expression and its role as potential target in multiple myeloma (MM). MCL1 gene regions are one the most amplified gene regions in several human cancers and Mcl-1 activity is often associated with therapy resistance and relapse. Mcl-1 binds to and sequesters the pro-apoptotic BH3 proteins, thereby preventing apoptosis. Mcl-1 is overexpressed on MM cells from newly diagnosed patients compared to normal plasma cells and in MM cells at relapse. This overexpression is furthermore associated with a shorter survival of these patients. Increased Mcl-1 expression can result either from genetic lesions or by induction through interaction with the bone marrow microenvironment. Its expression is correlated with the molecular heterogeneity of the myeloma patients; while the CCDN1 group has high BCL2 and low MCL-1 expression; the MMSET and MAF group has high MCL-1 and low BCL2 expression. Unlike Bcl-2 and Bcl-Xl, Mcl-1 has a large unstructured aminoterminus and its activity is mainly dependent on posttranslational modifications. The bone marrow microenvironment, by producing high levels of interleukin 6, also induces the upregulation of Mcl-1. Furthermore, our group recently demonstrated that not only stromal cells in the bone marrow microenvironment, but also MDSC (myeloid derived suppressor cells) induce survival of MM cells by increasing Mcl-1 levels through the AMPK pathway. As such, these data suggest the potential therapeutic benefit of targeting Mcl-1 in MM patients. Developing the first-generation inhibitors appeared to be challenging, especially in view of the occurrence of unwanted off target effects. Recent preclinical data with new, selective Mcl-1 inhibitors show promising anti-tumor effects both in vitro and in in vivo myeloma models, either alone or in combination with the Bcl-2 selective inhibitor, venetoclax, especially as it was demonstrated that high levels of MCL-1 are associated with venetoclax resistance in MM. In addition, it was also shown that proteasome inhibition can trigger Mcl-1 accumulation, further pointing to the importance of Mcl-1 inhibition. Induction of NOXA, as an inhibitor of Mcl-1, is also suggested as a therapeutic option, especially in combinations with other drugs. Clinically, following preclinical results, several new Mcl-1 inhibitors have entered phase I trials. Most of them are still recruiting patients, and as such too early to have results. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 26-26
Author(s):  
Hugo Henrique de Freitas Ferreira ◽  
Alessandra Suelen Jardim Silva ◽  
Lenilton Silva DA Silva Júnior ◽  
Gustavo Henrique de Medeiros Oliveira ◽  
Maria das Graças Pereira Araujo ◽  
...  

Introduction: Multiple myeloma (MM) is a malignant neoplasm characterized by the clonal proliferation of abnormal plasma cells in the bone marrow (OM). The average age of patients diagnosed with MM is approximately 70 years, being relatively uncommon in younger individuals. Objective: To report a case of a young patient with multiple myeloma. Case Description: A 42-year-old male patient presented with continuous and progressive low back pain for 3 months, associated with adynamia, weight loss (10 kg), episodes of constipation and bleeding in the oral cavity in this period. Examinations at the first appointment revealed moderate anemia (Hb 7.4 g / dL), leukocytosis, thrombocytopenia, hypercalcemia, and altered renal function (Cr 5.9 and Ur 178), chest tomography indicating vertebral fracture in T6, T11, L2 and L4. Referred for specialized follow-up, he performed electrophoresis of serum proteins with the presence of a monoclonal peak in the gamma globulin fraction. The immunofixation test confirmed monoclonality for IgA isotype and Kappa light chain (IgA / Kappa). The myelogram showed plasmacytosis of more than 50% of mononuclear cells in the bone marrow. He developed renal failure (with dosage of creatinine of 10.1 mg/ dL. and urea of 208 mg/dL) and hypercalcemia requiring dialysis therapy on the third day of hospitalization, having undergone chemotherapy with Bortezomib, cyclophosphamide and dexamethasone. During this period, infection by the multisensitive S. aureus in catheter occurred and, despite being treated with specific antibiotic therapy, it evolved with clinical worsening and hemodynamic instability and was referred to the Intensive Care Unit, going to death after 2 days. Conclusion: Young patients with MM may study with more aggressive characteristics. Despite the use of new therapeutic agents, more effective treatment strategies need to be studied more for patients in this age group. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5338-5338
Author(s):  
Finella MC Brito-Babapulle ◽  
Tanya Cranfield ◽  
Robert B Corser ◽  
Helen Dignum ◽  
Christopher James ◽  
...  

Abstract Mouse eosinophils have been shown in 2011 to be required for the maintenance of long lasting plasma cells in the bone marrow and in maintaining the bone marrow plasma cell microenvironment. Human eosinophils have been shown by Wong et al to support multiple myeloma cell proliferation via a mechanism independent of IL6. We looked at bone marrow biopsies taken from patients who had a paraprotein and in whom a diagnosis of multiple myeloma was suspected. These samples were taken solely for the purposes of diagnosisng multiple myeloma and were retrospectively reviewed from the point of view of degree of eosinophil infiltration and its correlation with tumour load, bone lytic lesions, plasma cell morphology, whether blastic, crystalline inclusions, Mott cells, flame cells and or lymphoplasmacytoid. There were no cases of IGD or E myeloma or osteosclerotic myeloma.Nonsecretory myeloma and cases of light chain myeloma with or without amyloid were included in the series. Biopsies were not performed from osteolytic lesion unless biopsy was necessary to make a diagnosis of myeloma. Myeloma was diagnosed when plasma cell infiltrate was greater than 10% on bone marrow aspirate with a paraprotein and or lytic lesions. Eosinophil infiltration did not correlate with any of the tumour clinicopathological markers but showed an inverse correlation with degree of plasmacytosis. Eosinophils were hardly ever found in marrow aspirates that had over 70% plasma cells. They were usually found in trephine sections of bone marrow in areas where there was Grade I/II fibrosis and were often found in close proximity to focal areas of plasma cell infiltration. Whether eosinophils play a role in preventing or maintaining malignant plasma cell recurrence is currently being studied. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4808-4808
Author(s):  
Shuang Geng ◽  
Jing Wang ◽  
Mingyi Chen ◽  
Wenming Wang ◽  
Yuhong Pang ◽  
...  

Abstract Extramedullary Plasmacytoma (EMP) is a minor yet devastating metastatic form of Multiple Myeloma (MM), shortening patients' survival from 10 years to 6 months on average. Genetic cause of EMP in MM is yet to be defined. Transcriptome difference between EMP+ patients and EMP- patients is studied here on single cell level by RNA Sequencing (RNA-Seq). We sorted CD38+CD138+ malignant plasma cells from bone marrow and peripheral blood samples by flow cytometry, then picked up single malignant plasma cell and performed single cell RNA-Seq with SmartSeq2 protocol followed by Tn5-based library preparation from bone marrow, peripheral blood and extramedullary tissue of EMP patients. From the single cell RNA-Seq results, in bone marrow we found differential gene expression between EMP+ and EMP- samples, such as CTAG2, STMN1 and RRM2. By comparing circulating malignant plasma cells in PBMC and malignant plasma cell from the sample EMP+ patient, we observed metastatic clone in blood with the same VDJ immunoglobulin heavy chain as in bone marrow. Several genes' expression of these metastatic cells are down-regulated than in bone marrow, such as PAGE2, GTSF1, DICER1. These genes may correlate with egress capability of MM cells into peripheral to become circulating plasma cells (cPCs), and EMP eventually. Disclosures No relevant conflicts of interest to declare.


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