Genetic aberrations and survival in plasma cell leukemia

Update on the Diagnosis and Classification of the Plasma Cell Neoplasms

The plasma cell neoplasms are malignancies of the most terminally differentiated cells in B-cell ontogeny and are usually associated with the production of a monoclonal immunoglobulin molecule or M protein. These malignancies include tumors whose clinical manifestations are directly attributable to the end-organ damage induced by the dysregulated proliferation of neoplastic plasma cells. In contrast, disorders, such as primary amyloidosis, have a paradoxically low burden of neoplastic plasma cells, rendered highly pathogenic by the end-organ damage induced by deposition of the secreted paraprotein. In this article, discussion focuses on plasma cell myeloma. The molecular pathogenesis of plasma cell myeloma is reviewed and the diagnosis of the plasma cell neoplasms discussed.

Epigenetics and microRNAs combine to modulate the MDM2/p53 axis in myeloma

Avoiding the inhibitory effects of p53 on cell growth is important for tumor progression. In this issue of Cancer Cell, Picchiorri et al. describe epigenetic silencing of MDM2-targeting microRNAs in multiple myeloma (MM), which generally appears to have intact p53 function. This provides the rationale for microRNA-targeted therapy for MM.

Plasma cell leukaemia and other aggressive plasma cell malignancies

Extramedullary plasma cell cancers, such as plasma cell leukaemia (PCL) and multiple extramedullary plasmacytomas (MEP) are very aggressive malignancies. These can be primary (de-novo) or secondary due to progressive prior multiple myeloma (MM). Recent reports suggest an increase in incidence of these disorders. Compared to MM, organ invasion is common in PCL, while soft tissue tumors involving the head, neck or paraspinal area are common sites for MEP. Markers of poor prognosis are frequently observed in these extramedullary forms of plasma cell cancers, and survival is significantly inferior compared to patients with MM. Conventional chemotherapeutic and radiotherapy approaches have been employed with variable results. Even high dose chemotherapy with autologous stem cell rescue has not been able to demonstrate consistent improvement in survival outcome. Although not specifically evaluated, novel anti-plasma cell agents, such as the proteasome inhibitor bortezomib, and immunomodulatory drugs, such as lenalidomide, appear to be active against these aggressive cancers. Clinical and translational research directed at improved understanding of disease biology and development of novel therapeutics is urgently needed.

Amplification of IGH/CCND1 fusion gene in a primary plasma cell leukemia case

The IGH/CCND1 fusion gene has been reported in many hematologic tumors such as mantle cell lymphoma, chronic lymphocytic leukemia, prolymphocytic leukemia, multiple myeloma, and plasma cell leukemia. We report a case of plasma cell leukemia showing five IGH/CCND1 fusion signals by interphase fluorescence in situ hybridization (FISH). Conventional cytogenetic analysis and multicolor spectral karyotyping showed a complex karyotype that did not include t(11;14). Metaphase FISH studies revealed three IGH/CCND1 fusion signals, two of which were amplified signals. These findings indicate that IGH/CCND1 fusion gene was amplified and interspersed in several chromosomes. The patient was treated with intensive chemotherapy. However, the clinical course was very aggressive. The amplification of the IGH/CCND1 fusion gene may contribute to the aggressive course of the disease. To our knowledge, this is the first case showing amplification of the IGH/CCND1 gene in plasma cell neoplasms.

Blockade of the MEK/ERK signalling cascade by AS703026, a novel selective MEK1/2 inhibitor, induces pleiotropic anti-myeloma activity in vitro and in vivo

This study investigated the cytotoxicity and mechanism of action of AS703026, a novel, selective, orally bioavailable MEK1/2 inhibitor, in human multiple myeloma (MM). AS703026 inhibited growth and survival of MM cells and cytokine-induced osteoclast differentiation more potently (9- to 10-fold) than AZD6244. Inhibition of proliferation induced by AS703026 was mediated by G0-G1 cell cycle arrest and was accompanied by reduction of MAF oncogene expression. AS703026 further induced apoptosis via caspase 3 and Poly ADP ribose polymerase (PARP) cleavage in MM cells, both in the presence or absence of bone marrow stromal cells (BMSCs). Importantly, AS703026 sensitized MM cells to a broad spectrum of conventional (dexamethasone, melphalan), novel or emerging (lenalidomide, perifosine, bortezomib, rapamycin) anti-MM therapies. Significant tumour growth reduction in AS703026- vs. vehicle-treated mice bearing H929 MM xenograft tumours correlated with downregulated pERK1/2, induced PARP cleavage, and decreased microvessels in vivo. Moreover, AS703026 (<200 nmol/l) was cytotoxic against the majority of tumour cells tested from patients with relapsed and refractory MM (84%), regardless of mutational status of RAS and BRAF genes. Importantly, BMSC-induced viability of MM patient cells was similarly blocked within the same dose range. Our results therefore support clinical evaluation of AS703026, alone or in combination with other anti-MM agents, to improve patient outcome.

Primary plasma cell leukemia: a Surveillance, Epidemiology, and End Results database analysis between 1973 and 2004

BACKGROUND

Primary plasma cell leukemia (PCL) is a rare plasma cell disorder, and current knowledge regarding survival in this disease is limited to small series of patients. Although there has been significant improvement in the survival of patients with multiple myeloma (MM) over the past few decades, it is not known whether there has been a similar trend for PCL.

METHODS

The authors analyzed the Surveillance, Epidemiology, and End Results (SEER) database to evaluate the characteristics and survival of patients who had PCL compared with those of patients who had MM.

RESULTS

Among 291 patients with PCL, the median age was 67 years (range, 19-98 years), the distribution of men and women was nearly equal, and the majority of patients were white (79.4%). The median overall survival (OS) was 4 months and the median disease-specific survival (DSS) was 6 months for patients with PCL; the 1-year, 2-year, and 5-year OS rates were 27.8%, 14.1%, and 6.4%, respectively. There were no survival differences noted according to sex or race. Patients aged<60 years were found to have a better median OS compared with patients aged>or=60 years (median OS, 7 months vs 3 months; P=.007), although the 5-year OS was equally poor in both groups (6.3% vs 6.4%, respectively). During the same period, 49,106 patients with MM were identified. Unlike MM, in which there has been a modest but statistically significant improvement in OS and DSS noted over time, no significant improvement was evident for PCL.

CONCLUSIONS

The poor long-term outcome and the lack of survival improvement in PCL suggest the need for better therapeutic options for these patients.

Frequent upregulation of MYC in plasma cell leukemia

Plasma cell leukemia (PCL) is a rare form of monoclonal gammopathy, which can originate de novo or evolve from multiple myeloma (MM) as a terminal leukemic phase. Previous cytogenetic studies of PCL have reported the presence of complex karyotypes with involvement of multiple unidentified chromosomal regions. We report here the analysis of 12 PCL (10 primary and two secondary) by metaphase and FISH analysis combined with oligonucleotide array data (244 k, Agilent). Interphase-FISH results were compared with those from a series of 861 newly diagnosed patients with MM. Cytogenetic analysis was successful on 11 patients, all of whom showed clonal chromosomal abnormalities. Compared with MM, t(11;14)(q13;q32) (42% versus 15%; P = 0.027) and t(14;16)(q32;q23) (25% versus 4%; P = 0.010) were more frequent in PCL, although neither the specific partner chromosome involved in the IgH translocation nor the ploidy status predicted for survival. Chromosomes 1, 8, 13, and 16 showed the highest number of copy number alterations with 8q24 being the chromosomal region most frequently involved. In eight of 12 patients we found abnormalities (translocations, one amplification, small deletions, and duplications) that directly targeted or were very close to MYC. Only four of these changes were detected by routine FISH analysis using commercial probes with the others exclusively detected by arrays. Quantitative reverse transcription polymerase chain reaction demonstrated that these different abnormalities were associated with increased levels of MYC mRNA. We conclude that MYC dysregulation by complex mechanisms is one of the major molecular events in the oncogenesis of PCL.

International Myeloma Working Group molecular classification of multiple myeloma: spotlight review

Myeloma is a malignant proliferation of monoclonal plasma cells. Although morphologically similar, several subtypes of the disease have been identified at the genetic and molecular level. These genetic subtypes are associated with unique clinicopathological features and dissimilar outcome. At the top hierarchical level, myeloma can be divided into hyperdiploid and non-hyperdiploid subtypes. The latter is mainly composed of cases harboring IgH translocations, generally associated with more aggressive clinical features and shorter survival. The three main IgH translocations in myeloma are the t(11;14)(q13;q32), t(4;14)(p16;q32) and t(14;16)(q32;q23). Trisomies and a more indolent form of the disease characterize hyperdiploid myeloma. A number of genetic progression factors have been identified including deletions of chromosomes 13 and 17 and abnormalities of chromosome 1 (1p deletion and 1q amplification). Other key drivers of cell survival and proliferation have also been identified such as nuclear factor- B-activating mutations and other deregulation factors for the cyclin-dependent pathways regulators. Further understanding of the biological subtypes of the disease has come from the application of novel techniques such as gene expression profiling and array-based comparative genomic hybridization. The combination of data arising from these studies and that previously elucidated through other mechanisms allows for most myeloma cases to be classified under one of several genetic subtypes. This paper proposes a framework for the classification of myeloma subtypes and provides recommendations for genetic testing. This group proposes that genetic testing needs to be incorporated into daily clinical practice and also as an essential component of all ongoing and future clinical trials.

Plasma cell myeloma

Plasma cell myeloma is a heterogenous disease with variable clinical presentation and outcome. The prognosis is largely determined by tumor biology. Newer therapeutic agents are rapidly changing the survival outlook of myeloma patients.

Emerging therapies for multiple myeloma

Multiple myeloma (MM) is a clonal plasma cell malignancy clinically characterized by osteolytic lesions, immunodeficiency, and renal disease. There are an estimated 750,000 people diagnosed with MM worldwide, with a median overall survival of 3 - 5 years. Besides chromosomal aberrations, translocations, and mutations in essential growth and tumor-suppressor genes, accumulating data strongly highlight the pathophysiologic role of the bone marrow (BM) microenvironment in MM pathogenesis. Based on this knowledge, several novel agents have been identified, and treatment options in MM have fundamentally changed during the last decade. Thalidomide, bortezomib, and lenalidomide have been incorporated into conventional cytotoxic and transplantation regimens, first in relapsed and refractory and now also in newly diagnosed MM. Despite these significant advances, there remains an urgent need for more efficacious and tolerable drugs. Indeed, a plethora of preclinical agents awaits translation from the bench to the bedside. This article reviews the scientific rationale of new therapy regimens and newly identified therapeutic agents - small molecules as well as therapeutic antibodies - that hold promise to further improve outcome in MM.

OH-2, a hyperdiploid myeloma cell line without an IGH translocation, has a complex translocation juxtaposing MYC near MAFB and the IGK locus

Multiple myeloma can be classified into hyperdiploid (HRD) (with 48-74 chromosomes) and non-hyperdiploid tumors (usually with immunoglobulin heavy chain translocations). The OH-2 human myeloma cell line (HMCL) retains the same HRD genotype as the primary tumor, with extra copies of chromosomes 3, 7, 15, 19, and 21. Both OH-2 and primary cells have a complex secondary translocation in which the IGK 3' enhancer is inserted between MYC and MAFB, resulting in dysregulation of both oncogenes. OH-2 provides a unique example of an HMCL and the corresponding primary tumor that are shown to share the same HRD genotype.

Plasma cell leukemia: a highly aggressive monoclonal gammopathy with a very poor prognosis

Plasma cell leukemia (PCL) is an aggressive variant of multiple myeloma and is characterized by the presence of >20% and/or an absolute number of greater 2 x 10(9)/L plasma cells circulating in the peripheral blood. PCL represents approximately 2-4% of all MM diagnosis and exists in two forms: primary PCL (PPCL, 60% of cases) presents de novo, whereas secondary PCL (SPCL, accounts for the remaining 40%) consists of a leukemic transformation in patients with a previously diagnosed MM. Because the mechanisms contributing to the pathogenesis of PCL are not fully understood, immunophenotyping, genetic evaluation (conventional karyotype, FISH, GEP and array-CGH), and immunohistochemistry are really important tools to investigate why plasma cells escape from bone marrow and become highly aggressive. Since treatment with standard agents and steroids is poorly effective, a combination of new drugs as part of the induction regimens and bone marrow transplant (autologous and allogeneic approaches) could nearly overcome the poor prognosis exhibited by PCL patients.

Complete remission of primary plasma cell leukemia with bortezomib, doxorubicin, and dexamethasone: a case report

Background

Plasma cell leukemia (PCL) is a rare lymphoproliferative disorder considered to be a variant of multiple myeloma. It is an aggressive disease with a poor clinical response to standard chemotherapeutic agents.

Case presentation

A novel regimen consisting of bortezomib, doxorubicin, and dexamethasone is currently under active evaluation for the treatment of multiple myeloma. We employed this combination as front-line chemoinduction therapy for a case of primary PCL.

Conclusion

Complete remission was achieved with rapid normalization of hematologic parameters. The combination of bortezomib, doxorubicin and dexamethasone demonstrates promise in the treatment of PCL.

Genetic aberrations including chromosome 1 abnormalities and clinical features of plasma cell leukemia

Plasma cell leukemia (PCL) is a rare form of plasma cell malignancy, few large series reported underlying genetic abnormalities. We systematically evaluated the genomic aberrations in 41 PCL patients by combining fluorescence in situ hybridization with cytoplasmic light chain immunofluorescence and correlated with their clinical outcome. The genomic aberrations in the 15 primary PCL (pPCL) and 26 secondary PCL (sPCL) were compared with 220 newly diagnosed multiple myeloma (MM) patients. There was no significant difference in the prevalence of genetic abnormalities in pPCL and sPCL but del(13q), t(4;14), 1q21 amplification and del(1p21) were more common in PCL than MM. Patients with pPCL had higher creatinine and beta(2)-microglobulin levels and tended to have a longer overall survival than patients with sPCL. In univariant analysis, PCL patients with t(4;14) (p=0.006) and del(1p21) (p=0.003) had shorter overall survivals. In multivariant analysis adjusting for all tested genetic factors as well as clinico-biologically relevant factors including C-reactive protein, calcium and beta(2)-microglobulin, t(4;14) remained a significant predictor for adverse overall survival in PCL (p=0.008).

Systemic joint laxity and mandibular range of movement

Primary plasma cell leukemia (pPCL) is a rare and aggressive form of multiple myeloma (MM) that is characterized by the presence of ≥20% circulating plasma cells. Overall survival remains poor despite advances of anti-MM therapy. The disease biology as well as molecular mechanisms that distinguish pPCL from non-pPCL MM remain poorly understood and, given the rarity of the disease, are challenging to study. In an attempt to identify key biological mechanisms that result in the aggressive pPCL phenotype, we performed whole-exome sequencing and gene expression analysis in 23 and 41 patients with newly diagnosed pPCL, respectively. The results reveal an enrichment of complex structural changes and high-risk mutational patterns in pPCL that explain, at least in part, the aggressive nature of the disease. In particular, pPCL patients with traditional low-risk features such as translocation t(11;14) or hyperdiploidy accumulated adverse risk genetic events that could account for the poor outcome in this group. Furthermore, gene expression profiling showed upregulation of adverse risk modifiers in pPCL compared to non-pPCL MM, while adhesion molecules and extracellular matrix proteins became increasingly downregulated. In conclusion, this is one of the largest studies to dissect pPCL on a genomic and molecular level.