Plasmacytoma Development Research Articles

Multiple Myeloma Complicated by Bone Plasmacytomas: Pathogenesis, Clinical Features, Treatment Approaches (A Literature Review)

Bone plasmacytoma is a malignant neoplasm consisting of plasma cells. It develops in the medullary cavities of the skeletal bones. The tumor can destroy bone cortex and proliferate into the surrounding tissues. In contrast to bone plasmacytomas, extramedullary plasmacytomas occur as a result of hematogenous dissemination in various tissues and organs. Based on literature data, the incidence of bone plasmacytomas at multiple myeloma (MM) onset is 7.0 % to 32.5 %, and at relapsed/progression ММ stages it is 9.0 % to 27.4 %. During bone plasmacytoma development, tumor cells acquire a number of new features: expression of adhesion molecules is decreased, new cytogenetic aberrations occur, autocrine secretion and neoangiogenesis are increased. The clinical course of MM complicated by bone plasmacytomas is characterized by minimal bone marrow damage, hemoglobin concentration within reference range, and decreased values of β2-microglobulin, paraprotein, calcium, and lactate dehydrogenase. Acute renal failure and immunoparesis are rare, early MM stages predominate. In literature, the MM form with multiple bone plasmacytomas is referred to as ‘macrofocal MM’. Survival rates of MM patients with bone plasmacytomas are at the intermediate level in terms of prognosis. The MM patients without plasmacytomas have the most favorable prognosis, whereas the MM patients with extramedullary plasmacytomas have the poorest prognosis. There is no unified approach to the treatment of MM complicated by bone plasmacytomas. There are no randomized prospective clinical studies on the efficacy of treating it. A successful use of proteasome inhibitors and immunomodulatory drugs was reported based on a small number of MM cases with plasmacytomas. Some studies proved the efficacy of auto-HSCT in this MM form. Bone plasmacytomas are treated with radiotherapy mainly after systemic chemotherapy.

Impact of Clinical Versus Biochemical Progression on Post-Progression Survival in Multiple Myeloma

Background: Overall response rate and response duration in newly diagnosed multiple myeloma (ndMM) has increased in the last decade. However, majority of patients eventually progress and receive multiple lines of therapy. Progression in MM is defined by rise in monoclonal protein and/or clinical manifestations of end-organ damage. However, there is a lack of evidence on the prognostic implication of pattern of progression in the current era. We have hypothesized that patients with clinical manifestations of end-organ damage at first progression have an inferior post-progression overall survival (OS) compared to those with biochemical progression alone.Method: We evaluated all ndMM patients between 1/1/2008 and 12/31/2015 at the Cleveland Clinic. Key inclusion criterion was patients experiencing first progression requiring an additional line of therapy. Patients with primary refractory disease and those in continued 1st remission at latest follow-up were excluded. Progression was categorized into 2 groups: Biochemical Progression (BP) and Clinical Progression (CP; implying CRAB features). Patients with CP were further stratified based on the presence of extramedullary disease (EM): CP+EM and CP-EM. Progression-free survival (PFS) and OS from first progression were estimated with Kaplan-Meier curves and compared among groups with log-rank test. Cox analysis was used to identify prognostic factors for OS and PFS. Potential prognostic factors included progression pattern, age, gender, race, ISS stage at diagnosis, FISH cytogenetics at diagnosis, metaphase cytogenetics at diagnosis, time from diagnosis to first progression, best response at first remission, frontline autologous stem cell transplant (ASCT), and whether progression occurred while on therapy.Results: A total of 527 patients with ndMM were evaluated, among which, 257 experiencing 1st progression were included in our analysis. The median age at progression was 64 years. The median time from diagnosis to first progression was 23 months. An autologous stem cell transplantation (ASCT) after induction therapy in 1st remission was performed in 26% of patients. At 1st progression, BP alone was noted in 52% (n=134), CP -EM in 34% (n=87) and CP+EM in 14% (n=36) of patients. In the CP-EM group, the most common mode of progression was development of new bone lesions (76%) followed by anemia (33%), renal insufficiency (18%) and hypercalcemia (13%), with ≥1 mode in approximately one-third of patients. In the CP+EM group, the most common mode of EM progression was development of new plasmacytomas (89%), followed by emergence of circulating plasma cells (14%), with 1 patient having both. A total of 84% of patients progressed on anti-myeloma therapy, which reflects the contemporary practice of continuous therapy in MM. After first progression, 68% received proteasome inhibitors (PIs), 64% received immunomodulatory drugs (IMiDs) and 11% received monoclonal antibodies (MoAbs). Salvage ASCT in 2nd remission was performed in 12% of patients.A total of 105 patients (41%) were alive at latest follow-up, with the median follow-up of survivors being 26 months from 1st progression. Median time from diagnosis to 1st progression was shorter in the CP+EM (12 months) compared to CP-EM (25 months) and BP (24 months) groups (P<0.001). There was no significant difference in the progression pattern by depth of 1st remission. The 2-year post-progression OS in BP, CP-EM and CP+EM groups was 81%, 40% and 12% respectively (P<0.001; Figure I). The 2-year post-progression PFS in the respective groups were 35%, 8% and 7% respectively (P<0.001). On multivariable analysis for OS, independent prognostic factors included progression pattern, age at 1st progression and high-risk FISH cytogenetics at diagnosis (Table I).Conclusion: In the era of PIs, IMiDs and MoAbs, the pattern of 1st progression in MM has a strong and independent prognostic impact on post-progression OS. Patients progressing with clinical manifestations of end-organ damage or extramedullary disease have an inferior PFS and OS compared to those progressing with biochemical criteria alone. These results should be further validated in large prospective studies with data on FISH cytogenetics at relapse. It has clinical implication at the individual level and can also inform the design of clinical trials in relapsed MM. [Display omitted] DisclosuresMajhail:Anthem, Inc.: Consultancy; Incyte: Honoraria; Atara: Honoraria.

Heat Shock Protein 70 Inhibitor, Alone or in Combination with Bortezomib, Prevented Plasmacytoma Development in Immunodeficient Mice Transplanted with Myeloma Cell Lines

Introduction: HSP70 has an integrative role in protein degradation due to the interaction with many pathways, such as ubiquitin proteasome (UPS), unfolded protein response (UPR) and autophagy. In multiple myeloma (MM) HSP70 is overexpressed and helps to prevent proteotoxic stress and cell death caused by overload of unfolded/misfolded proteins produced by tumor cells. Aims: To explore the role of HSP70 inhibition, isolated or in association with proteasome inhibitor, as therapeutic strategy for MM through in vitro and in vivo analyses. Methods: RPMI8226-LUC-PURO and U266-LUC-PURO bioluminescent cell lines were treated with HSP70 inhibitor (VER155008- 50 μM or 80μM) and proteasome inhibitor (bortezomib 100nM) for evaluation of apoptosis induction by flow cytometry using annexin V and propidium iodide. NOD.Cg-rkdcscid Il2rgtm1Wjl/SzJ immunodeficient mice were used for plasmacytoma xenograft model and treated with intravenous VER155008 (40mg/kg) and bortezomib (1mg/kg), immediately after transplant of RPMI8226-LUC-PURO and U266-LUC-PURO bioluminescent cell lines (N=3 for each group, including controls, bortezomib, VER155008, and combination of bortezomib and VER155008). Bioluminescence was measured in IVIS Kinetic (Capiler Life Science) once a day for seven days. Results: Bortezomib used as single treatment was able to induce apoptosis in RPMI8226-LUC-PURO cell line: the best result for in vitro studies RPMI8226-LUC-PURO was 65% of late apoptosis after treatment with bortezomib. On the other hand, U266-LUC-PURO cell line presented higher percentage of apoptosis when treated with bortezomib and VER155008 combination: U266-LUC-PURO cell line presented more than 60% of late apoptosis after VER155008 (80μM) combined with bortezomib, showing that inhibition of HSP70 could overcome U266-LUC-PURO resistance to bortezomib alone. Mice treated with VER155008, alone or in combination with bortezomib, showed complete inhibition of tumor growth (absence of bioluminescence) for both cell lines when compared with control group after one week of treatment (p<0.001, Two-way ANOVA). Therefore, in vivo studies using mice treated with VER155008, alone or in combination with bortezomib, prevented tumor development after one week of treatment, independent of the cell line used in the xenotransplant. Conclusion: Our study shows that HSP70 and proteasome inhibitors combination induced apoptosis in tumor cells in vivo for both MM cell lines. Since HSP70 is overexpressed in MM and connects several signaling pathways that maintain cell survival, such as UPS, UPR and autophagy, it can represent a key role to establish a new approach for the treatment of MM. Financial support: FAPESP 2010/17668-6 and CNPq (155272/2013-6). UNIFESP Ethics Committee (0219/12). DisclosuresNo relevant conflicts of interest to declare.

Due to interleukin-6 type cytokine redundancy only glycoprotein 130 receptor blockade efficiently inhibits myeloma growth.

Interleukin-6 has an important role in the pathophysiology of multiple myeloma where it supports the growth and survival of the malignant plasma cells in the bone marrow. It belongs to a family of cytokines which use the glycoprotein 130 chain for signal transduction, such as oncostatin M or leukemia inhibitory factor. Targeting interleukin-6 in plasma cell diseases is currently evaluated in clinical trials with monoclonal antibodies. Here, efforts were made to elucidate the contribution of interleukin-6 and glycoprotein 130 signaling in malignant plasma cell growth in vivo In the xenograft severe combined immune deficiency model employing our interleukin-6-dependent plasma cell line INA-6, the lack of human interleukin-6 induced autocrine interleukin-6 production and a proliferative response to other cytokines of the glycoprotein 130 family. Herein, mice were treated with monoclonal antibodies against human interleukin-6 (elsilimomab/B-E8), the interleukin-6 receptor (B-R6), and with an antibody blocking glycoprotein 130 (B-R3). While treatment of mice with interleukin-6 and interleukin-6 receptor antibodies resulted in a modest delay in tumor growth, the development of plasmacytomas was completely prevented with the anti-glycoprotein 130 antibody. Importantly, complete inhibition was also achieved using F(ab')2-fragments of monoclonal antibody B-R3. Tumors harbor activated signal transducer and activator of transcription 3, and in vitro, the antibody inhibited leukemia inhibitory factor stimulated signal transducer and activator of transcription 3 phosphorylation and cell growth, while being less effective against interleukin-6. In conclusion, the growth of INA-6 plasmacytomas in vivo under interleukin-6 withdrawal remains strictly dependent on glycoprotein 130, and other glycoprotein 130 cytokines may substitute for interleukin-6. Antibodies against glycoprotein 130 are able to overcome this redundancy and should be explored for a possible therapeutic window.

Anti-CD19 Chimeric Antigen Receptor-Modified T Cells for Multiple Myeloma

Multiple myeloma is a disease formed by malignant plasma cells that accumulate in the bone marrow. The lifetime risk of multiple myeloma in the U.S. is 1/140, making it the second most common hematologic malignancy and it was expected that 22,350 new cases to be diagnosed in the US in 2013 [1]. In the past decade, we have witnessed dramatic changes in the treatment of multiple myeloma. Proteasome inhibitors such as bortezomib and carfilzomib target the ubiquitin pathway, resulting in cytotoxic injury due to disruption of protein degradation in myeloma cells. When compared with melphalan–prednisone–lenalidomide (MPR), combine therapy with high-dose melphalan and stem-cell transplantation significantly prolonged progression-free survival among patients with multiple myeloma who were in the age group of 65 years or younger [2]. Discovery of anti-tumor efficacy of the graft vs. myeloma response, such as CAR T cell therapy seems likely to herald the beginning of a revolution in the treatment of multiple myeloma. Several observations have fostered optimism that more specific immunotherapeutic approach such as chimeric antigen receptors (CARs) modified autologous T cells might exhibit more potent anti-myeloma activity with less toxicity. Currently all ongoing CAR studies employ firstgeneration anti-CD19 CAR and a second-generation version, usually with CD28. In pre-clinical studies, anti-myeloma second-generation CARs are developed to target the Lewis Y antigen (Ley), B Cell Maturation Antigen (BCMA), cell surface glycoprotein CS1 and CD38. Ley is overexpressed in many epithelial malignancies. In a recent study, multiple myeloma cell lines were injected into a immunocompromised mice followed by the injection of anti-Ley CAR T cells that significantly exhibited prolonged survival and delayed development of symptomatic plasmacytomas [3]. The National Cancer Institute (NCI) has recently identified BCMA which is expressed on most multiple myeloma cells. Anti-BCMA CAR is a second-generation CD28-based CAR that showed quite favourable efficacy and toxicity profiles against multiple myeloma [4]. CS1 is over-expressed in multiple myeloma cells. The CD28-based anti-CS1 CAR-modified natural killer (NK) cells revealed cytotoxicity against multiple myeloma cell lines and prolonged survival in patients with multiple myeloma [5]. CD38 is a transmembrane glycoprotein and a second-generation 4-1BB-based anti-CD38 CAR was proved to be effective against multiple myeloma cell lines [6]. In a phase I/II study, anti-CD38 antibody daratumumab showed a remarkable efficacy for the treatment of patients with multiple myeloma [7]. The most clinical experience so far has been with anti-CD19 CARs that have been utilized in several phase I trials targeting B cell malignancies. Genetically engineered CARs that couple with an anti-CD19 single chain Fv domain to intracellular T-cell signalling domains of the T-cell receptor transmit cytotoxic T lymphocytes to antigen expressing cells. CAR–mediated T-cell responses can further be enhanced with the addition of a costimulatory domain. CD3 zeta domain has been used in CARmodified T cells that lead to the activation of T-cell signal and it has been referred as a first generation CAR. In recent competitive repopulation studies, CAR designs have been executed based on the addition of a single (second generation) or multiple co-stimulatory domains (third generation) [8]. In preclinical models, it has been found that antitumor activity and in vivo persistence of chimeric antigen receptors significantly increase with the inclusion of CD137 (4-1BB) signalling domain as compared with the inclusion of CD3-zeta chain alone [9]. CTL019 is a chimeric antigen receptor that includes a CD137 (4-1BB) signalling domain and is expressed with the use of lentiviral-vector technology for gene transfer and permanent T cell modification.

UCHL1 Is a Biomarker of Aggressive Multiple Myeloma Required for Disease Progression

The success of proteasome inhibition in multiple myeloma highlights the critical role for the ubiquitin-proteasome system (UPS) in this disease. However, there has been little progress in finding more specific targets within the UPS involved in myeloma pathogenesis. In an unbiased screen of de-ubiquitinase activity, we previously found the ubiquitin hydrolase UCH-L1 to be frequently over-expressed in B-cell malignancies, including myeloma. Using a transgenic mouse model, we also found that aberrant expression of UCH-L1 is sufficient to drive the development of spontaneous B-cell lymphomas and plasmacytomas, demonstrating its oncogenic activity. Whether and how UCH-L1 affects the clinical behavior of myeloma, however, is not known. Here we show that UCH-L1 is a potent negative prognostic factor that is essential for the dissemination and progression of myeloma. We found high levels of UCHL1 to predict early progression in newly diagnosed patients; a finding reversed in studies including bortezomib. We also found high UCHL1 levels to be a critical factor in the superiority of bortezomib over high-dose dexamethasone in relapsed patients. High UCHL1 partially overlaps with, but is distinct from, known genetic risks including 4p16 rearrangement and 1q21 amplification. Using an orthotopic mouse model, we found UCH-L1 depletion delays myeloma dissemination and causes regression of established disease. We conclude that UCH-L1 is a biomarker of aggressive myeloma that may be an important marker of bortezomib response, and may itself be an effective target in disseminated disease. DisclosuresGalardy:Mission Therapeutics: Research Funding.

Changes in Nuclear Orientation Patterns of Chromosome 11 during Mouse Plasmacytoma Development

Studying changes in nuclear architecture is a unique approach toward the understanding of nuclear remodeling during tumor development. One aspect of nuclear architecture is the orientation of chromosomes in the three-dimensional nuclear space. We studied mouse chromosome 11 in lymphocytes of [T38HxBALB/c]N mice with a reciprocal translocation between chromosome X and 11 (T38HT(X;11)) exhibiting a long chromosome T(11;X) and a short chromosome T(X;11) and in fast-onset plasmacytomas (PCTs) induced in the same strain. We determined the three-dimensional orientation of chromosome 11 using a mouse chromosome 11 specific multicolor banding probe. We also examined the nuclear position of the small translocation chromosome T(X;11) which contains cytoband 11E2 and parts of E1. Chromosomes can point either with their centromeric or with their telomeric end toward the nuclear center or periphery, or their position is found in parallel to the nuclear border. In T38HT(X;11) nuclei, the most frequently observed orientation pattern was with both chromosomes 11 in parallel to the nuclear border (“PP”). PCT cells showed nuclei with two or more copies of chromosome 11. In PCTs, the most frequent orientation pattern was with one chromosome in parallel and the other pointing with its centromeric end toward the nuclear periphery (“CP”). There is a significant difference between the orientation patterns observed in T38HT(X;11) and in PCT nuclei (P < .0001).

Abstract A04: The tumor microenvironment is the main source of IL-6 for plasmacytoma development in mice.

Abstract The development of targeted interventions for hematopoietic neoplasms of the B-lymphocyte lineage, such as multiple myeloma (MM), may benefit from preclinical experimental model systems in which complex interactions of neoplastic and nonmalignant bystander cells in the tumor microenvironment (TME) can be genetically dissected. Here we employ peritoneal plasmacytomagenesis in mice, which is strictly dependent on the pro-inflammatory cytokine, interleukine 6 (IL-6), to demonstrate that the nonmalignant bystanders are the main source of IL-6 for tumor development. B cell derived IL-6 is dispensable. The finding that lack of IL-6 in the TME significantly delays tumor onset in mice supports translational research efforts to target IL-6 production in bone marrow stroma cells for myeloma treatment and prevention. Citation Format: Timothy R. Rosean, Van S. Tompkins, Ramakrishna Sompallae, Lyse A. Norian, Herbert C. Morse, III, Thomas J. Waldschmidt, Siegfried Janz. The tumor microenvironment is the main source of IL-6 for plasmacytoma development in mice. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A04.

Time to Development of Treatment-Emergent Extramedullary and Osseous Plasmacytomas in the Era of Novel Agents: An Analysis of Upfront Regimens in Newly Diagnosed MM Incorporating Lenalidomide and Bortezomib

Introduction: The introduction of proteasome inhibitors (PI) and immunomodulatory derivatives (IMIDs) has been associated with substantial improvement in overall survival of patients with multiple myeloma (MM). In the era of novel agents, there have also been concerns of an increased incidence of extramedullary disease (EMD), and of a hypothetical risk that combined use of PIs and IMIDs for frontline treatment might select more rapidly for aggressive clones that could precipitate EMD. It is difficult to determine the true frequency of treatment-emergent EMD, as incidence rates may be influenced by the impact of specific therapies, as well as confounded by changes in overall survival, and the increased use of sensitive imaging modalities.Objective: The primary objective of our study was to evaluate whether the addition of lenalidomide (Len) to bortezomib (Bort)-based front-line regimens precipitated the more rapid development of treatment-emergent EMD, either in the form of extraosseous or osseous extramedullary plasmacytomas. Potential risk factors for and the prognostic impact of EMD development were also examined.Patients-Methods: We performed an IRB-approved retrospective comprehensive medical chart review of 117 MM patients enrolled in 8 clinical trials of first-line treatment with Bort-based regimens with Len (Bort-Len-Dexamethasone [known as RVD], its combination with cyclophosphamide [Cy], vorinostat or liposomal doxorubicin) or without Len (specifically, Bort monotherapy; MPV; CyBorDex; MPV-CNT0328). In these 2 treatment groups, the development of EMD was assessed in the form of extraosseous (soft-tissue mass distant from bone) or osseous (mass originating from cortical bone) plasmacytomas. The primary endpoint was time from diagnosis until development of plasmacytoma (osseous; extraosseous; or any of the 2), based on radiologic imaging, biopsy and/or physical examination, with censoring at last disease follow-up date for patients who did not develop EMD. We compared the rates of EMD in these 2 patient cohorts through sensitivity analyses at truncated follow-up times of 5- and 7-years, to control for any potential confounding effects of shorter follow-up in patients receiving combined Bort-based therapy with vs. without Len.Results: The median follow-up time from diagnosis was 6.1 years (range 0.1-10.2 years) for the entire cohort; and 5.6 years (range 1.5-7.4) vs. 8.9 (range 0.1-10.2), respectively, for Bort-based treatment with vs. without Len. Treatment-emergent EMD was observed in the form of osseous (n=32, 27.4%), extraosseous (n=19, 16.2%) or any osseous or extraosseous plasmacytoma (n=40, 34.2%). Stage III ISS or low Hb (<12 g/dL) at diagnosis was associated with shorter time to development of extraosseous plasmacytomas (univariate analyses, p=0.02, for both parameters). After development of extraosseous plasmacytomas, the median OS was 0.9 years (range 0.1-4.8 years). In sensitivity analyses with follow-up times truncated at 5 years (rates of EMD and 95% CI summarized in Table 1) or 7 years (data not shown), the rates of any form of EMD showed no statistically significant difference between the 2 treatment groups (log-rank tests p>0.1 for all comparisons).Conclusion: Based on these results, there is no evidence to suggest that combination Bort- Len-based front-line therapy precipitates more rapid development of EMD. Conversely, the development of extra osseous plasmacytoma was associated with poor OS regardless of prior treatment. Further confirmation with extended follow-up, as well as studies of treatment effect, correlatives (incorporating both genotypic and phenotypic features), and the incidence as well as outcome of EMD are warranted.Table 1:Sensitivity analyses (follow-up times truncated at 5 years)Bort-Len based treatment (N=69 patients)Bort-based treatment without Len (N=48 patients)P-value (Log-rank tests)Hazard ratio Osseous Plasmacytoma (%, 95% CI)0.54280.78(0.36,1.73)At 2 years7 (3-7)11 (5,25)At 4 years17 (10,29)25 (14,41)At 5 years24 (15,38)27 (16,44)Total cases1411Extraosseous Plasmacytoma (%, 95% CI)0.16910.51(0.19,1.36)At 2 years4(1,13)5(1,17)At 4 years8(3,18)15(7,30)At 6 years12(6,25)23(13,40)Total cases79Any Osseous or Extraosseous Plasmacytoma (%, 95% CI)0.42360.76(0.38,1.50)At 2 years10(5,20)16(8,30)At 4 years24(15,36)29(17,45)At 6 years30(20,44)37(24,53)Total cases1815 DisclosuresLaubach:Novartis: Research Funding; Onyx Pharmaceuticals: Research Funding. Ghobrial:Millennium/Takeda: Membership on an entity’s Board of Directors or advisory committees; Onyx: Membership on an entity’s Board of Directors or advisory committees; BMS: Membership on an entity’s Board of Directors or advisory committees; Celgene: Membership on an entity’s Board of Directors or advisory committees. Mitsiades:Millennium Pharmaceuticals: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Amgen : Research Funding; Johnson & Johnson: Research Funding.

Evaluation of Anti-Neoplastic Effects of a New Hemostatic Agent Ankaferd Blood Stopper on Myeloma Cell Line and Plasmocytoma Development in Balb/c Mice: Results of the First in Vitro and in Vivo Study

Ankaferd Blood Stopper (ABS), a unique traditional herbal mixture, has been used topically to stop bleeding for centuries in Anatolia. As well as ABS has been used as a blood-stopping agent, it may also have a considerable therapeutic benefit, because of its anti-infective, anti-neoplastic, and wound healing properties. The aim of this study is to investigate the anti-neoplastic effects of the ABS on myeloma cell line, in vitro and on the plasmocytoma development in Balb/c mice by intraperitoneal injection of pristane, in vivo. We therefore sought to evaluate the efficacy of ABS on MM cells and to study the modulation of cell-death pathways. The cytotoxicity of ABS against the MM cell lines (RPMI-8226, and ARH-77) was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-dye reduction assay. Responses to ABS by RPMI-8226 and ARH-77 cell lines were dose dependent but not time dependent. The IC50 values for RPMI 8226 and ARH 77 myeloma cell lines in 24h were 12,84 μL/mL and 13,86 μL/mL, respectively. Various cell-death characteristics such as caspase-3, Bcl-2, Bax were studied in response to ABS, but we couldn’t demonstrate specific features of apoptotic cell death, in vitro. We have also investigated the effect of the ABS on the pristane (2.6.10.14-tetramethylpentadecane)-induced plasmacytoma (PCT) development on six-week-old BALB/c mice. Three groups of mice were treated with intraperitoneal ABS (1 mg/kg, 0.5mg/kg, and 0,1mg/kg) per-week for eight weeks after pristane-induced PCT development. The study was stopped at twelfth week, the remaining mice were autopsied, and peritoneal tissues were examined histologically for PCTs. A database of different groups’ mice was analyzed using Kaplan-Meier and Cox regression statistics based on variables. Kaplan-Meier analysis revealed a difference of the survival of pristane-induced alone between the groups of pristane-induced plus ABS 1 mg/kg, 0.5mg/kg, and 0.1mg/kg. (Log-rank, p=0.016; p<0.001 and p<0.001; respectively). The present results indicate that direct anti-tumor effect of ABS on pristane-induced PCT and significantly increased survival. This hypothesis needs to now be further investigated in clinical trials. DisclosuresNo relevant conflicts of interest to declare.

Plasmacytomagenesis in Eμ-v-abl transgenic mice is accelerated when apoptosis is restrained

AbstractMice susceptible to plasma cell tumors provide a useful model for human multiple myeloma. We previously showed that mice expressing an Eµ-v-abl oncogene solely develop plasmacytomas. Here we show that loss of the proapoptotic BH3-only protein Bim or, to a lesser extent, overexpression of antiapoptotic Bcl-2 or Mcl-1, significantly accelerated the development of plasmacytomas and increased their incidence. Disease was preceded by an increased abundance of plasma cells, presumably reflecting their enhanced survival capacity in vivo. Plasmacytomas of each genotype expressed high levels of v-abl and frequently harbored a rearranged c-myc gene, probably as a result of chromosome translocation. As in human multiple myelomas, elevated expression of cyclin D genes was common, and p53 deregulation was rare. Our results for plasmacytomas highlight the significance of antiapoptotic changes in multiple myeloma, which include elevated expression of Mcl-1 and, less frequently, Bcl-2, and suggest that closer attention to defects in Bim expression is warranted.

Modulation of the host microenvironment by a common non-oncolytic mouse virus leads to inhibition of plasmacytoma development through NK cell activation

Although many cells undergo transformation, few actually develop into tumours, due to successful mechanisms of immunosurveillance. To investigate whether an infectious agent may play a role in this process, the growth of a plasmacytoma was investigated in mice infected by lactate dehydrogenase-elevating virus. Acutely infected animals were significantly protected against tumour development. The mechanisms responsible for this protection were analysed in mice deficient for relevant immune cells or molecules and after in vivo cell depletion. This protection by viral infection correlated with NK cell activation and with IFN-γ production. It might also be related to activation of NK/T-cells, although this remains to be proven formally. Therefore, our results indicated that infections with benign micro-organisms may protect the host against cancer development, through non-specific stimulation of the host's innate immune system and especially of NK cells.

Serum Level of Lactate Dehydrogenase is a Useful Clinical Marker to Monitor Progressive Multiple Myeloma Diseases: A Case Report.

To follow the progression of multiple myeloma (MM) disease, serum lactate dehydrogenase (LDH) levels are as useful markers as beta-2 microglobulin and monoclonal immunoglobulin. With this study, we have presented a case of a patient with a multiple myeloma which was fulminant course, whose LDH levels were normal at the onset of diagnosis increasing as 27 times more than normal as the disease progressed and who showed the development of extramedullary plasmacytomas. The patient, an 80-year-old female, was diagnosed with stage IIIA IgA type multiple myeloma and melphalan-prednisolon (MP) treatment was started. Although the LDH levels were low during the diagnosis and chemotherapy, the LDH levels increased up to 7557 U/L following the progression and occurrence of extramedullary plasmacytomas and the patient died. During the observation of the patient with MM, if the LDH levels are abnormally high, the progression of the disease should be considered after eliminating the other causes. Bone marrow aspiration and biopsy should be examined and the progression or relapse should be shown. On the other hand, the patients with LDH levels are high should be considered to have added plasmacytomas, the whole body should be examined at an early stage before the development of clinical symptoms and early treatment should be started.

Extramedullary Pasmacytoma Masquerading as Chalazion

Extramedullary plasmacytoma (EMP) is a rare entity that belongs to the category of non-Hodgkin lymphoma. EMP make up 4% of all plasma cell tumors and occur mainly in the upper aerodigestive tract. Primary plasmacytoma involving the orbit is rare. There is a relation between solitary plasmacytoma and subsequent development of multiple myeloma. As no predictors of progression have been identified patients need indefinite follow-up. The authors report a case of EMP involving the eyelid in an otherwise healthy adult female.

IgM multiple myeloma presenting with spinal cord compression caused by a plasmacytoma: A case report

BackgroundIgM multiple myeloma is rare disorder, which has clinical, laboratory and radiological manifestations that are consistent with both multiple myeloma and Waldenstrom's macroglobulinaemia.Case presentationAn 83 years Welsh lady presented with clinical and radiological features consistent with spinal cord compression. Further investigations confirmed the diagnosis of IgM multiple myeloma. Following localized radiotherapy and five courses of melphalan and prednisolone, the patient achieved partial remission of her myeloma. Later on, the patient had disease progression in the form of rising serum IgM level and the development of multiple plasmacytomas. She was treated with thalidomide, cyclophosphamide, dexamethasone and radiotherapy, which resulted in the control of her disease for one year. To our knowledge, this is the second case of IgM myeloma presenting with a plasmacytoma and the first case of IgM myeloma presenting with cord compression caused by plasmacytomas.ConclusionUnlike other types of multiple myeloma IgM myeloma is rarely complicated by plasmacytomas. However, spinal cord compression caused by plasmacytomas in this type of myeloma is extremely rare. Nevertheless, the same lines of management, e.g. cytotoxic chemotherapy and local radiotherapy that are applied to other types of myeloma can be successfully utilized.

Insertion of Myc into Igh Accelerates Peritoneal Plasmacytomas in Mice

Gene-targeted mice that contain a His6-tagged mouse c-Myc cDNA, Myc(His), inserted head to head into different sites of the mouse immunoglobulin heavy-chain locus, Igh, mimic the chromosomal T(12;15)(Igh-Myc) translocation that results in the activation of Myc in the great majority of mouse plasmacytomas. Mice carrying Myc(His) just 5' of the intronic heavy-chain enhancer Emu (strain iMyc(Emu)) provide a specific model of the type of T(12;15) found in a subset (approximately 20%) of plasmacytomas that develop "spontaneously" in the gut-associated lymphoid tissue (GALT) of interleukin-6 transgenic BALB/c (C) mice. Here we show that the transfer of the iMyc(Emu) transgene from a mixed genetic background of segregating C57BL/6 x 129/SvJ alleles to the background of C increased the incidence of GALT plasmacytomas by a factor of 2.5 in first-generation backcross mice (C.iMyc(Emu) N1). Third-generation backcross mice (C.iMyc(Emu) N3, approximately 94% C alleles) were hypersusceptible to inflammation-induced peritoneal plasmacytomas (tumor incidence, 100%; mean tumor onset, 86 +/- 28 days) compared with inbred C mice (tumor incidence, 5% on day 150 after tumor induction). Peritoneal plasmacytomas of C.iMyc(Emu) N3 mice overexpressed Myc(His), produced monoclonal immunoglobulin, and exhibited a unique plasma cell signature upon gene expression profiling on mouse Lymphochip cDNA microarrays. These findings indicated that the iMyc(Emu) transgene accelerates plasmacytoma development by collaborating with tumor susceptibility alleles of strain C and circumventing the requirement for tumor precursors to acquire deregulated Myc by chromosomal translocation.

Unusual cutaneous involvement during plasma cell leukaemia phase in a multiple myeloma patient after treatment with thalidomide: a case report and review of the literature

We report the case of a 54-year-old African-American male with IgG multiple myeloma (MM) with disease resistant to multiple chemotherapy regimens and immunomodulatory treatment with thalidomide. In spite of achieving a partial remission of short duration, his disease accelerated to peripheral plasmacytosis and subsequent development of cutaneous plasmacytomas. The malignant plasma cells derived from the dermal lesions were CD45+, CD38+, CD138+ and matched the immunophenotype of the plasmacytes during the leukaemic phase. Occurrence of extramedullary lesions in the setting of MM treated with thalidomide is of concern, although currently there are very few reports describing this association. We discuss the possible relationship between the patient's unusual disease course and the administered chemo- and immunotherapy. The significance of the changes in adhesion molecules, especially CD138 and CD56, relevant to the development of cutaneous plasmacytomas is discussed.

Evolving therapeutic role of bisphosphonates in multiple myeloma

Sir, We read the interesting article by Morgan and Davies (2005) on the novel therapeutic strategies such as thalidomide and derivatives, proteasome inhibitors, and targeted therapy in the maintenance setting or in the induction phase of myeloma treatment prior to high-dose therapy (HDT). They emphasised the importance of the characterisation of the myeloma genome before selecting a treatment, the diagnosing of myeloma at an early stage to deliver the novel treatment in the natural history of their disease, and the establishment of the response rates and lengths of remission before novel combinations could be compared with HDT. However, there is no mention about the novel antitumour activity of bisphosphonates (BPs) besides its inhibiting effects on bone resorption in multiple myeloma (MM). As is well known, BPs are used to treat osteoclast-mediated bone diseases, including osteoporosis, Paget's disease, hypercalcemia of malignancy, bone metastases, and bone disease associated with MM (Berenson et al, 1996; Jantunen, 2002). Current views suggest that BPs may affect differentiation and recruitment of osteoclast precursors (Hughes et al, 1989) or alter the capability of mature osteoclasts to resorb bone by altering the permeability of the osteoclast membranes to small ions (Sato et al, 1991). As a member, the more potent nitrogen-containing group of BPs, zoledronic acid, inhibits protein prenylation, thus affecting osteoclast function and survival. As protein prenylation is required by all cells, not just osteoclasts, the possibility that nitrogen-containing BPs could also affect the viability of tumour cells arises (Green, 2003). Several studies have clearly demonstrated that BPs are cytostatic to tumour cells in vitro, induce apoptosis, inhibit cell adhesion and interfere with the metastatic process (Aparicio et al, 1998). We have recently demonstrated that zoledronic acid induced antiproliferative and apoptotic effects on MM cell lines in vitro by activating protein kinase C and increasing extracellular calcium concentration, and these effects augmented with dexamethasone and thalidomide addition to zoledronic acid (Ural et al, 2003). Bisphosphonates may exert their antimyeloma effect by inhibiting release of bone marrow-derived growth factor, such as transforming growth factor β and insulin-like growth factor into marrow, by inducing apoptosis of MM cells, by downregulating production of interleukin 6 from bone marrow stroma, and by stimulating γδ T-cell-mediated antiplasma cell activity in the marrow (Mundy and Yoneda, 1998; Kunzmann et al, 2000). Therefore, zoledronic acid may augment in vivo the therapeutic action of dexamethasone and thalidomide through direct effects on myeloma cells as well as by inhibition of paracrine and autocrine signals by bone marrow stromal cells (Corral et al, 1996; Tassone et al, 2000). In this context, the results of clinical studies have suggested that BPs may reduce tumor burden and may improve survival of patients with MM (Berenson et al, 1998; Mundy and Yoneda, 1998). In addition, objective remission or inhibition of disease progression has been reported in patients with MM who underwent pamidronate treatment alone (Dhodapkar et al, 1998). In another study of ours, we demonstrated that zoledronic acid was able to increase disease-free survival in the pristane-induced plasmacytoma, a model with no direct bone involvement, in BALB/c mice model (Avcu et al, 2005). In this study, zoledronic acid treatment markedly impeded intraperitoneal plasmacytoma development. It also decreased tumour burden and extramedullary tumour growth in mice. Moreover, in contrast to many other animal tumours studied, which used high doses of BPs (Guenther et al, 2002; Croucher et al, 2003), the zoledronic acid dose of 20 μg kg−1 week−1 s.c., which was efficacious in the murine plasmacytoma model is approximately equivalent to the approved clinical dose for the treatment of the skeletal complications of MM (4 mg every 3–4 weeks i.v.). All these results raise the possibility that nitrogen-containing BPs, such as zolederonic acid, with their direct antitumour effects, may be valuable adjuncts to the novel therapeutic strategies in the treatment of MM.

Location of Myc, Igh, and Igk on Robertsonian fusion chromosomes is inconsequential for Myc translocations and plasmacytoma development in mice, but Rb(6.15)‐carrying tumors prefer Igk–Myc inversions over translocations

The location of the Myc and immunoglobulin (Ig) loci on metacentric Robertsonian (Rb) fusion chromosomes may affect the development of mouse plasmacytomas (Pcts) by changing the probability with which chromosomal Myc-Ig translocations occur. To test this hypothesis, we induced Pcts in BALB/c (C) mice that carried Rb(4.12) and/or Rb(6.15) chromosomes. The Rb mice developed Pcts (n = 198) with similar onset and incidence to that in the inbred C mice. Karyotyping of 70 Rb-carrying Pcts demonstrated that in these tumors, just as in their counterparts in inbred C mice, the Igh heavy-chain locus was translocated with Myc more often than was the Igk light-chain locus. Pcts harboring Igh or Igk on normal and Rb chromosomes showed no bias toward either in generating Myc translocations. These findings indicated that the location of Myc, Igh, and Igk on normal or Rb chromosomes is inconsequential for Myc translocation and Pct development. In contrast, in Rb(6.15) mice, in which chromosomal inversions competed with chromosomal translocations for Igk-Myc juxtapositions, the former occurred more frequently than the latter in the resulting Pcts. This suggested that spatial proximity of Igk and Myc on the same chromosome facilitates the rearrangement of these loci. Myc translocation-dependent mouse Pct may provide a good model system for furthering our understanding of the relationship of higher-order genome organization in the interphase nucleus, origin of chromosomal translocations, and development of cancer.

The impact of p53 loss on murine plasmacytoma development.

Mouse plasmacytomas (PCTs) are characterized by c-myc-activating translocations that juxtapose c-myc on chromosome 15 onto one of the immunoglobulin loci (IgH on chromosome 12, IgK on chromosome 6, or IgA on chromosome 16). To assess the impact of p53 loss on PCT genesis, we induced PCTs in p53-deficient BALB/cRb6.15 mouse strains. We show that p53 loss accelerates tumor development and causes a shift in the typical translocation patterns. PCTs that carry variant T(6;15) translocations become as frequent as those with typical T(12;15) translocations (41.66%). In addition, in the absence of p53, the number of translocation-negative PCTs increases from less than 1% to 16.66%. It is noteworthy that neither the shortened latency periods nor the shift in translocation patterns had an impact on the incidence of PCT development. The 42.2% incidence in N3p53-/- mice is similar to the percentages recorded in groups of conventional BALB/cAn mice. The possible mechanisms underlying the accelerated tumorigenesis and the shift in translocation patterns are discussed.