Identification of translocation products but not K-RAS mutations in memory B cells from patients with multiple myeloma.

BACKGROUND: Several laboratories have shown that cells with a memory B-cell phenotype can have the same clonotype as multiple myeloma tumor cells. DESIGN AND METHODS: The aim of this study was to determine whether some memory B cells have the same genetic alterations as their corresponding multiple myeloma malignant plasma cells. The methodology included sorting multiple myeloma or memory B cells into RNA stabilizing medium for generation of subset-specific polymerase chain reaction complementary DNA libraries from one or 100 cells. RESULTS: Cells with the phenotype of tumor plasma cells (CD38(++)CD19(-)CD45(-/+)CD56(-/+/++)) or memory B cells (CD38(-)/CD19(+)/CD27(+)) were isolated by flow activated cell sorting. In samples from all four patients with multiple myeloma and from two of the three with monoclonal gammopathy of undetermined significance, we identified memory B cells expressing multiple myeloma-specific oncogenes (FGFR3; IGH-MMSET; CCND1 high) dysregulated by an IGH translocation in the respective tumor plasma cells. By contrast, in seven patients with multiple myeloma, each of whom had tumor plasma cells with a K-RAS61 mutation, a total of 32,400 memory B cells were analyzed using a sensitive allele-specific, competitive blocker polymerase chain reaction assay, but no K-RAS mutations were identified. CONCLUSIONS: The increased expression of a specific "early" oncogene of multiple myeloma (monoclonal gammopathy of undetermined significance) in some memory B cells suggests that dysregulation of the oncogene occurs in a precursor B-cell that can generate memory B cells and transformed plasma cells. However, if memory B cells lack "late" oncogene (K-RAS) mutations but express the "early" oncogene, they cannot be involved in maintaining the multiple myeloma tumor, but presumably represent a clonotypic remnant that is only partially transformed.

Multiparametric flow cytometry profiling of neoplastic plasma cells in multiple myeloma.

BACKGROUND AND AIM: The clinical impact of multiparametric flow cytometry (MFC) in multiple myeloma (MM) is still unclear and under evaluation. Further progress relies on multiparametric profiling of the neoplastic plasma cell (PC) compartment to provide an accurate image of the stage of differentiation. The primary aim of this study was to perform global analysis of CD expression on the PC compartment and subsequently to evaluate the prognostic impact. Secondary aims were to study the diagnostic and predictive impact. DESIGN AND METHODS: The design included a retrospective analysis of MFC data generated from diagnostic bone marrow (BM) samples of 109 Nordic patients included in clinical trials within NMSG. Whole marrow were analyzed by MFC for identification of end-stage CD45(-) /CD38(++) neoplastic PC and registered the relative numbers of events and mean fluorescence intensity (MFI) staining for CD19, CD20, CD27, CD28, CD38, CD44, CD45, CD56, and isotypes for cluster analysis. RESULTS: The median MFC-PC number was 15%, and the median light microscopy (LM)-PC number was 35%. However, the numbers were significant correlated and the prognostic value with an increased relative risk (95% CI) of 3.1 (1.7-5.5) and 2.9 (1.4-6.2), P < 0.0003 and P < 0.004 of MFC-PC and LM-PC counts, respectively. Unsupervised clustering based on global MFI assessment on PC revealed two clusters based on CD expression profiling. Cluster I with high intensity for CD56, CD38, CD45, right-angle light-scatter signal (SSC), forward-angle light-scatter signal (FSC), and low for CD28, CD19, and a Cluster II, with low intensity of CD56, CD38, CD45, SSC, FSC, and high for CD28, CD19 with a median survival of 39 months and 19 months, respectively (P = 0.02). CONCLUSIONS: The MFC analysis of MM BM samples produces diagnostic, prognostic, and predictive information useful in clinical practice, which will be prospectively validated within the European Myeloma Network (EMN). © 2010 International Clinical Cytometry Society.

Regulation of the CD56 promoter and its association with proliferation, anti-apoptosis and clinical factors in multiple myeloma.

Multiple myeloma (MM) is an incurable B-cell malignancy characterised by uncontrolled growth and accumulation of malignant plasma cells in the bone marrow. Aberrant expression of CD56 in patients with MM is thought to contribute to a worsened disease course and metastasis. We therefore investigated the regulation of the CD56 promoter in relation to typical clinical factors. We used qPCR and FACS to measure the expression levels of CD56, and potential regulatory factors in patients with MM and related these with MM progression/prognosis. The transcription factors BTBD3, Pax5, RUNX1 and MMSET were positively associated with CD56 expression, as was CYCLIN D1, which is involved in disease progression, anti-apoptosis and proliferation. RUNX1 was negatively associated with the survival of stem-cell transplanted patients. Our findings propose four potential activators of the CD56 promoter and for CD56 to be involved in proliferation and anti-apoptosis, leading to disease progression in MM.

A phase I clinical trial of the histone deacetylase inhibitor belinostat in patients with advanced hematological neoplasia.

PURPOSE: To determine the safety, dose-limiting toxicity and maximum tolerated dose (MTD) of the novel hydroxamate histone deacetylase inhibitor belinostat (PXD101) in patients with advanced hematological neoplasms. PATIENTS AND METHODS: Sequential dose-escalating cohorts of three to six patients with hematological malignancies received belinostat administered as a 30-min i.v. infusion on days 1-5 of a 21-d cycle. Experience from a parallel dose-finding study in patients with solid tumors influenced the selection of the final dose. RESULTS: Sixteen patients received belinostat at one of three dose levels: 600 mg/m(2)/d (three patients), 900 mg/m(2)/d (three patients) and 1000 mg/m(2)/d (10 patients), the dose determined to be the MTD in a phase I solid tumor study [Steele et al. (2008) Clin Cancer Res, 14, 804-10]. The most common treatment-related adverse events (all grades) were nausea (50%), vomiting (31%), fatigue (31%) and flushing (31%). No grade 3 or 4 hematological toxicity compared with baseline occurred except one case of grade 3 lymphopenia. There were two related grade 4 adverse events of renal failure observed. Both events occurred in patients with multiple myeloma and had similar characteristics, i.e. an acute episode of decrease in renal function (pre-existing nephropathy in one patient), with a metabolic profile and decrease in tumor burden consistent with tumor lysis syndrome. No other related grade 4 events were noted. The only related grade 3 events noticed in more than one patient were fatigue and neurological symptoms (one patient had status epilepticus in association with uremia and one patient had paresthesia), all other related grade 3 events occurred in single patients. No cardiac events were noted. No complete or partial remissions were noted in these heavily pre-treated (median of four prior regimens) patients. However, five patients, including two patients with diffuse large-cell lymphoma [including one patient with transformed chronic myelocytic leukaemia (CLL)], two patients with CLL and one patient with multiple myeloma, achieved disease stabilization in of two to nine treatment cycles. CONCLUSIONS: Intravenous belinostat at 600, 900 and 1000 mg/m(2)/d is well tolerated by patients with hematological malignancies. The study was carried out in parallel to a similar dose-finding study in patients with solid tumors, in which the MTD was determined to be 1000 mg/m(2)/d days 1-5 in a 21-d cycle. This dose can also be recommended for phase II studies in patients with hematological neoplasms.

Frequent hypermethylation of DBC1 in malignant lymphoproliferative neoplasms.

Allelic loss at chromosome 9q31-34 is a frequent event in many lymphoproliferative malignancies. Here, we examined DBC1 at 9q33.1 as a potential target in lymphomagenesis. DBC1 is a putative tumor suppressor that has been shown to be involved in the regulation of cell growth and programmed cell death. The methylation status of the DBC1 promoter CpG island was examined by methylation-specific PCR, bisulfite sequencing, and methylation-specific melting curve analysis. DBC1 was hypermethylated in 5 of 5 B-cell-derived lymphoma cell lines, 41 of 42 diffuse large B-cell lymphomas, 24 of 24 follicular lymphomas, 5 of 5 mantle cell lymphomas, 4 of 4 small lymphocytic lymphomas, 1 of 2 lymphoplasmacytoid lymphomas, and in 12 of 12 acute lymphoblastic leukemias, but was unmethylated in 1 case of splenic marginal zone lymphoma, in 12 of 12 multiple myelomas, in 24 of 24 reactive lymph nodes, and in 12 of 12 samples of blood lymphocytes from random donors. DBC1 hypermethylation was associated with transcriptional silencing in lymphoma cell lines, and reexpression of this gene could be induced by treatment with the demethylating agent, 5-aza-2'-deoxycytidine. Our data suggest that hypermethylation of the DBC1 promoter region is a frequent event during the development of lymphoproliferative malignancies, and that DBC1 hypermethylation may serve as a marker for these cancers.

High serum YKL-40 concentration is associated with severe bone disease in newly diagnosed multiple myeloma patients.

OBJECTIVES: In multiple myeloma (MM) YKL-40 is present in the bone marrow microenvironment and is suggested to play a role in remodelling of the extracellular matrix. Here, the association between serum YKL-40 and severity of bone disease in MM is investigated. METHODS: Serum YKL-40 was measured in 34 MM patients at diagnosis. Bone disease was assessed by radiography and biochemical markers of bone metabolism. Patients were treated with conventional chemotherapy and followed for up to 30 months. RESULTS: Patients with a serum YKL-40 elevated above the age specific reference range (56%) had a higher total X-ray score (P = 0.003) and higher levels of the markers of bone resorption serum C-terminal telopeptide of collagen type I (P = 0.003), urine pyridinoline (P = 0.04) and urine deoxypyridinoline (P = 0.002), while the levels of urine N-terminal telopeptide of collagen type I (NTX-1) and the markers of bone formation equalled those seen in patients with a normal serum YKL-40. Serum YKL-40 level (beta = 7.6; P = 0.002) and urine NTX-1 (log(2)) (beta = 3.5; P = 0.006) were independent predictors of total X-ray score at diagnosis. Patients with elevated serum YKL-40 at diagnosis had shorter time to first osteolytic event compared to patients with normal serum YKL-40 (12 months vs. not reached; Log rank test: P = 0.03). CONCLUSIONS: Newly diagnosed MM patients with elevated serum concentrations of YKL-40 have more severe bone destruction including increased bone resorptive activity and shorter time to progression of bone disease. At this point, a potential role for YKL-40 in myeloma-related bone disease must be considered.

Serum YKL-40 concentrations in newly diagnosed multiple myeloma patients and YKL-40 expression in malignant plasma cells.

OBJECTIVES: A potential role in cancer biology is suggested for YKL-40 (CHI3L1, HC gp-39). The purpose of this study was to evaluate the clinical value of serum YKL-40 (sYKL-40) in multiple myeloma (MM) and to examine YKL-40 expression in malignant plasma cells (MM PCs). METHODS: sYKL-40 was measured by enzyme-linked immunosorbent assay (ELISA) in 82 patients with newly diagnosed MM. YKL-40 expression in immunophenotypically defined plasma cells was investigated by double-labelled immunohistochemistry in 21 MM patients and by real-time reverse transcriptase polymerase chain reaction (RT-PCR) in cDNA archives generated by global RT-PCR in seven controls, 14 patients with monoclonal gammopathy of undetermined significance (MGUS), 45 MM patients, nine patients with extramedullary myeloma (exMM), and seven human myeloma cell lines (HMCLs). RESULTS: sYKL-40 was elevated above a constructed reference range for healthy controls in 29% of the patients investigated. Patients with elevated sYKL-40 had reduced overall survival and event-free survival when compared to patients with normal sYKL-40, but sYKL-40 level was defeated by beta(2)-microglobulin in the multivariate analyses. Intramedullary MM PCs lacked significant expression of YKL-40, but high levels of YKL-40 expression were seen in extramedullary MM PCs from one exMM patient and in six HMCLs. Further investigations of other bone marrow (BM) cells showed YKL-40 expression in megakaryocytes, neutrophils and adherent cells from long-term BM cultures. CONCLUSIONS: In newly diagnosed MM-patients, a sYKL-40 elevated above the reference range predicts a poor clinical outcome, and YKL-40 is expressed by other BM cells than MM PCs. At this point, routine measurements of sYKL-40 are not warranted, but YKL-40 should be considered as a potential player in the pathophysiology of MM.

Autologous stem cell transplantation in multiple myeloma: outcome in patients with renal failure.

The impact of renal failure on prognosis of multiple myeloma patients treated with high-dose chemotherapy and stem cell support is incompletely studied. A total of 137 patients received high-dose chemotherapy with autologous transplantation at our centre. The patient population was divided into three groups based on their estimated creatinine clearance (Ccr); renal failure defined as Ccr < 60 mL/min: Group A: normal renal function both at diagnosis and at transplant (n = 78), Group B: renal failure at diagnosis but normal renal function at transplant (n = 30), Group C: renal failure both at diagnosis and at transplant (n = 29). There were no differences in the number of stem cells harvested, time to engraftment or response to transplantation between the groups. Ten of the patients in Group C had a normalisation of renal function post-transplant. Significantly longer hospitalisation, increased use of blood products and increased number of infections were seen in Group C compared to Groups A and B. The transplant-related mortality was 17% in Group C compared to 0% and 1% in Groups B and A respectively. Eight patients were on dialysis during transplant and four of these died within the first 100 d post-transplant. Disease response was similar in the three groups. Overall survival was significantly longer in Group A than in Groups B and C. High-dose chemotherapy with autologous transplantation is feasible in MM with renal failure. Whereas patients with moderate renal insufficiency seem to benefit from this treatment, patients in need for dialysis at the time of transplant must be carefully evaluated before proceeding to high-dose chemotherapy.

Molecular and clinical follow-up after treatment of multiple myeloma.

Multiple myeloma (MM) is a B cell malignancy characterized by accumulation of plasma cells (PCs) in the bone marrow. Traditional methods for the detection of minimal residual disease (MRD) measure the presence of monoclonal immunoglobulin protein secreted by the malignant PCs. However, changes in the level of MRD in MM may span 6 logs, and methods with a high sensitivity and dynamic range are necessary for quantitating MRD in MM. The two main technologies used in MRD detection are flow cytometry and patient-specific reverse transcription (RT) PCR. Patient-specific RT-PCR has high sensitivity and may be beneficial in monitoring patients receiving allogeneic transplantation. However, for the MRD evaluation of autotransplants, where few patients achieve molecular remission, flow cytometry monitoring seems to be sufficient.