Bone marrow angiogenesis in 400 patients with monoclonal gammopathy of undetermined significance, multiple myeloma, and primary amyloidosis.

PURPOSE: To determine whether bone marrow (BM) angiogenesis progressively increases along the spectrum of plasma cell disorders ranging from monoclonal gammopathy of undetermined significance (MGUS) to advanced myeloma. EXPERIMENTAL DESIGN: Four hundred patients with the following disorders were studied: MGUS (76 patients); smoldering (indolent; early-stage) multiple myeloma (SMM; 112 patients); newly diagnosed, active multiple myeloma (MM; 99 patients); relapsed (advanced) multiple myeloma (RMM; 26 patients); and primary amyloidosis (AL; 87 patients). Forty-two normal control BM samples were studied for comparison. BM angiogenesis was studied in a blinded manner by immunohistochemical staining for CD34 to identify microvessels. RESULTS: The median (range) microvessel density (MVD) per x400 high power field was 1.3 (0-11) in the controls, 1.7 (0-10) in AL, 3 (0-23) in MGUS, 4 (1-30) in SMM, 11 (1-48) in newly diagnosed MM, and 20 (6-47) in RMM; P < 0.001. MVD was significantly higher in MGUS, SMM, newly diagnosed MM, and RMM compared with controls and AL; P < 0.001. MVD was not significantly different between controls and AL. By grading, high-grade angiogenesis was present in 0% of controls and AL, 1% of MGUS, 3% of SMM, 29% of newly diagnosed MM, and 42% of RMM; P < 0.001. MVD correlated with the BM plasma cell labeling index (rho = 0.46, P < 0.001) and BM plasma cell percentage (rho 0.5, P < 0.001). Survival was 28 months in SMM and newly diagnosed MM with high-grade angiogenesis, compared with 53 months for those with low- and intermediate-grade angiogenesis; P = 0.02. CONCLUSIONS: BM angiogenesis progressively increases along the spectrum of plasma cell disorders, from the more benign MGUS stage to advanced myeloma, indicating that angiogenesis may be related to disease progression.     

Cytokine and chemokine profiles in multiple myeloma; significance of stromal interaction and correlation of IL-8 production with disease progression

Multiple myeloma (MM) is a product of interactions between tumor plasma cells and multiple cell types native to the bone marrow (BM). We have used antibody array technology to examine the proteins produced by BM stromal cells in response to stimulation by BM taken from patients diagnosed with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and MM. We observed increased production of the chemokine IL-8 by stromal cells co-cultured with supernatants from bone marrow cells of patients with active myeloma. IL-8 production is correlated with active disease and is dependent upon IL-1beta and NF-kappaB signaling. Consistent with the pro-angiogenic activity of IL-8, increased BM microvessel density (MVD) correlated with stimulation of stromal cell IL-8 production. In addition, the majority of MM cell lines and MM patient plasma cells were found to express IL-8 receptors CXCR1 and CXCR2. We conclude that stromal cell IL-8 production parallels MM disease activity, is IL-1beta induced, and correlates with bone marrow angiogenesis.     

Multiple myeloma. An update on diagnosis and management

Patients with multiple myeloma must be differentiated from those with monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM). The plasma cell labeling index is helpful in differentiating MGUS or SMM from multiple myeloma (MM). No difference in survival was noted between patients given a single alkylating agent and those given a combination of alkylating agents. Alternating cycles of interferon alpha 2 and VBMCP (vincristine, BCNU, melphalan, cyclophosphamide, prednisone) produced a complete or near-complete response in 41% of patients. Allogeneic or syngeneic bone marrow transplantation has produced some benefit. Autologous bone marrow transplantation is potentially applicable to treat more patients. Major problems are eradication of myeloma cells from the bone marrow and removal of myeloma cells from autologous bone marrow. Purging of myeloma cells with monoclonal antibodies and chemotherapy may be helpful. Stem cells from autologous peripheral blood are being used for rescue after high-dose chemotherapy and total-body irradiation.     

Ras oncogene expression and DNA content in plasma cell dyscrasias: a flow cytofluorimetric study

Using bivariate flow cytofluorometry, we have determined the nuclear DNA distribution and the expression of the p21 protein (coded by the Ha-ras oncogene) in the bone marrow (BM) cells of five solid tumour patients having histologically normal BM and in those of 57 patients with plasma cell dyscrasia (28 with monoclonal gammopathies of undertermined significance, MGUS, and 29 with multiple myeloma, MM). All normal and MGUS and 21/29 (72.4%) MM BM had diploid modal DNA content and 8/29 (27.6%) MM BM had both diploid and hyperdiploid cell populations. In normal and MGUS BM, the level of the p21 oncoprotein was low and uniform in all G0/G1, S and G2 cells (median fluorescence values in arbitrary units were 6.1 and 7.5, respectively). The level of p21 was increased both in different aliquots of G0/G1 cells and in the S and G2 cells in diploid MM (median value for G0/G1 cells was 20), and especially in MM with hyperdiploid clones (median value for hyperdiploid cells was 40.5, P less than 0.005 with respect to normal and MGUS BM and less than 0.005 with respect to diploid MM BM). The p21 expression was greater in patients with advanced (stage III) than in earlier MM (stages I + II) (P less than 0.005), and it was directly related to the BMPC infiltration (r = 0.7; P less than 0.005). Since p21 expression is greater in MM than in both normal and MGUS BM, Ha-ras could be involved in the malignant plasma cell transformation that distinguishes MM from MGUS.     

Blood-based risk stratification for pre-malignant and symptomatic plasma cell neoplasms to improve patient management

Standard risk stratification (sRisk) guides clinical management in monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM) and multiple myeloma (MM). Nonetheless, clinical results are considerably heterogeneous among patients with similar risk status. Blood and bone marrow samples from 276 MGUS, 56 SMM and 242 MM in regular clinical practice were analyzed at diagnosis by flow cytometry. Higher levels of aberrant circulating plasma cells (cPC) (> 0.0035% of leukocytes), combined with albumin, beta2-microglobuline and lactate-dehydrogenase levels, offered minimally-invasive risk stratification (RcPC) with results comparable to sRisk. RcPC and sRisk 10-year progression-free-survival (10y-PFS) rates were: 93.8% vs. 95.1% for low-risk, 78.4% vs. 81.7% for intermediate-risk and 50.0% vs. 47.8% for high-risk MGUS; 58.3% vs. 57.8% low-risk, 44.4% vs. 45.8% intermediate-risk and 8.9% vs. 15.0% high-risk SMM; and 44.4% vs. 44.4% low-risk, 36.1% vs. 36.8% intermediate-risk, and 13.3% vs. 16.2% high-risk MM. Circulating-PC > 0.0035% vs. cPC<0.0035% was an independent prognostic factor for PFS (HR=4.389, P=1.2×10^-15, Harrell C-statistic =0.7705±0.0190) and over-all survival (OS, HR=4.286, 2.3×10^-9, Harrell C-statistic =0.8225±0.0197) that complemented sRisk in patients with low-sRisk (10y-PFS rates 48.1% vs. 87.3%, P=1.2×10^-8) and intermediate-sRisk (10y-PFS rates 28.9% vs. 74.1%, P=8.6×10^-12). Patients with high cPCs values are associated with higher proliferation and lower apoptosis rates of PC. Circulating-PC > 0.0035% identified MGUS, SMM and MM patients at higher risk of progression or death and predicted a cohort of patients that after relapse from stringent complete response showed shorter OS. These patients could benefit from early consolidation therapy, tandem ASCT or intensive maintenance.     

C-Myc在多发性骨髓瘤中的研究进展

多发性骨髓瘤(multiple myeloma,MM)是一种浆细胞恶性增殖性疾病,其特点为克隆性浆细胞在骨髓中异常增殖,发病率在血液系统肿瘤中排第2位.C-Myc是一种原癌基因,在人类的多种实体肿瘤和血液肿瘤中异常高表达.近年来相关研究表明,C-Myc的表达增强与肿瘤的不良预后息息相关.从癌前病变单克隆丙种球蛋白病(m...     

14q32 translocations and monosomy 13 observed in monoclonal gammopathy of undetermined significance delineate a multistep process for the oncogenesis of multiple myeloma. Intergroupe Francophone du Myélome.

Clonal plasma cells in monoclonal gammopathy of undetermined significance (MGUS) have been shown to bear copy number chromosome changes. To extend our knowledge of MGUS to structural chromosomal abnormalities, we have performed fluorescence in situ hybridization experiments with probes directed to the 14q32 and 13q14 chromosomal regions in 100 patients with either MGUS or smoldering multiple myeloma (SMM). 14q32 abnormalities were observed in at least 46% of patients with MGUS/SMM, with these abnormalities being present in the majority of clonal plasma cells. Whereas t(11;14)(q13;q32) occurs in 15% of MGUS/SMM patients, an incidence similar to that of overt multiple myeloma (MM) patients, translocation t(4;14)(p16;q32) is observed in only 2% of these cases [P = 0.002 for difference with t(11;14)], as compared with 12% in MM patients (P = 0.013). Monoallelic deletions of the 13q14 region were found in 21% of patients, with two types of situations. In half of the evaluable patients, and especially in patients with SMM, the deletion is present in the majority of clonal plasma cells, as in MM, whereas in the other half of the evaluable patients (essentially in MGUS patients), it is observed in subclones only. These data enable us to elaborate a plasma cell oncogenesis model from MGUS to MM.     

Immunoglobulin Gene Rearrangement in Plasma Cell Dyscrasias: Detection of Small Clonal Cell Populations in Peripheral Blood and Bone Marrow

The bone marrow (BM) and peripheral blood (PB) samples of 71 patients with plasma cell dyscrasias were analysed by the Southern blot technique for the presence of clonal immunoglobulin (Ig) gene rearrangements. 53% of BM samples examined were archival material such as air dried BM slides or frozen trephine biopsies. The results were related to bone marrow plasmacytosis as determined by cytology and flow cytometry, and other clinical parameters. Clonal Ig gene rearrangements were found in BM samples of 45 (83%) of 54 MM patients and in 3 of 6 patients with monoclonal gammopathy of unknown significance (MGUS). Clonal cell populations in the PB were detected in 11 (30%) of 37 examined MM patients, but in none of the patients with MGUS or solitary plasmacytoma of bone. PB involvement was associated with progressive disease. Circulating monoclonal cells were significantly associated with higher M-protein levels (p 0.05). Thus, circulating clonal precursor cells are encountered more frequently in active MM.     

Understanding biology to tackle the disease: Multiple myeloma from bench to bedside,and back

Answer questions and earn CME/CNE Multiple myeloma (MM) is a cancer of antibody‐producing plasma cells. The pathognomonic laboratory finding is a monoclonal immunoglobulin or free light chain in the serum and/or urine in association with bone marrow infiltration by malignant plasma cells. MM develops from a premalignant condition, monoclonal gammopathy of undetermined significance (MGUS), often via an intermediate stage termed smoldering multiple myeloma (SMM), which differs from active myeloma by the absence of disease‐related end‐organ damage. Unlike MGUS and SMM, active MM requires therapy. Over the past 6 decades, major advancements in the care of MM patients have occurred, in particular, the introduction of novel agents (ie, proteasome inhibitors, immunomodulatory agents) and the implementation of hematopoietic stem cell transplantation in suitable candidates. The effectiveness and good tolerability of novel agents allowed for their combined use in induction, consolidation, and maintenance therapy, resulting in deeper and more sustained clinical response and extended progression‐free and overall survival. Previously a rapidly lethal cancer with few therapeutic options, MM is the hematologic cancer with the most novel US Food and Drug Administration‐approved drugs in the past 15 years. These advances have resulted in more frequent long‐term remissions, transforming MM into a chronic illness for many patients. CA Cancer J Clin 2014;64:422–444. © 2014 American Cancer Society.     

Massive parallel IGHV gene sequencing reveals a germinal center pathway in origins of human multiple myeloma

Human multiple myeloma (MM) is characterized by accumulation of malignant terminally differentiated plasma cells (PCs) in the bone marrow (BM), raising the question when during maturation neoplastic transformation begins. Immunoglobulin IGHV genes carry imprints of clonal tumor history, delineating somatic hypermutation (SHM) events that generally occur in the germinal center (GC). Here, we examine MM-derived IGHV genes using massive parallel deep sequencing, comparing them with profiles in normal BM PCs. In 4/4 presentation IgG MM, monoclonal tumor-derived IGHV sequences revealed significant evidence for intraclonal variation (ICV) in mutation patterns. IGHV sequences of 2/2 normal PC IgG populations revealed dominant oligoclonal expansions, each expansion also displaying mutational ICV. Clonal expansions in MM and in normal BM PCs reveal common IGHV features. In such MM, the data fit a model of tumor origins in which neoplastic transformation is initiated in a GC B-cell committed to terminal differentiation but still targeted by on-going SHM. Strikingly, the data parallel IGHV clonal sequences in some monoclonal gammopathy of undetermined significance (MGUS) known to display on-going SHM imprints. Since MGUS generally precedes MM, these data suggest origins of MGUS and MM with IGHV gene mutational ICV from the same GC B-cell, arising via a distinctive pathway.     

Selective depletion of human myeloma clonogenic stem cells from bone marrow cell preparations by a plasma-cell reactive antibody and complement

The monoclonal antibody MM4 reacts with human myeloma cells from plasma cell dyscrasia (PCD)-derived cell lines and bone marrow (BM) biopsies from PCD patients, but not with normal BM or peripheral blood mononuclear (PBM) cells. We examined cytotoxicity of MM4 and rabbit complement (MM4:C') on mixtures of normal BM mononuclear cells and myeloma cells from three different PCD-derived cell lines, RPMI 8226, GM 1312, or ARH-77. For cell preparations containing 10% myeloma cells, treatment with MM4 (500 micrograms per 10(5) cells, 4 degrees C, 60 min) and two cycles of complement (1:8, 23 degrees C, 2 x 30 min) consistently eliminated 2 logs or more of clonogenic myeloma stem cells, as determined by colony growth assays and limiting dilution analysis (99.4%, 98.9%, and 99.96% reduction of RPMI 8226, GM 1312, and ARH-77 cells, respectively). The majority of normal marrow progenitors were spared (inhibition of CFU-C: 10-13%; BFU-E: 0%). These observations suggest that MM4 may be useful for selective depletion of human myeloma clonogenic stem cells from bone marrow ex vivo.     

Deep Sequencing Reveals Myeloma Cells in Peripheral Blood in Majority of Multiple Myeloma Patients

IntroductionThe evaluation of myeloma cells in multiple myeloma (MM) patients has generally been limited to the assessment of bone marrow involvement because of the sensitivity limitations of traditional minimal-residual-disease–detection methods.Materials and MethodsWe developed a sequencing-based method to identify myeloma cells in bone marrow (BM) and peripheral blood (PB) samples, based on their unique immunoglobulin gene rearrangements, that can detect cancer clones at levels well below 1 in 1 million leukocytes (0.0001%). In this multisite study, we used this sequencing method to determine the fraction of patients with myeloma cells in their PB at diagnosis and posttreatment time points.ResultsUsing this sequencing approach, we detected myeloma cells in the PB in the vast majority of MM patients (44/46, 96%). We demonstrated a clear correlation (R² = 0.57) between myeloma clone levels in paired BM and PB samples, and noted that PB clone levels were approximately 100-fold lower than levels in BM samples. The sequencing assay demonstrated a clear sensitivity advantage in the BM compartment and at least equivalent sensitivity in the PB compared with that of monoclonal-protein results.ConclusionThis study highlights the promise of a blood-based, sequencing minimal-residual-disease assay that can be used to measure MM disease burden at different time points and various disease stages.     

Quantification of bone marrow plasma cell infiltration in multiple myeloma: usefulness of bone marrow aspirate clot with CD138 immunohistochemistry

Accurate quantification of plasma cells (PCs) in bone marrow (BM) is critical for diagnosis and assessment of treatment response in patients with multiple myeloma (MM). We compared the % of BM PC quantified by 250 cell differential count on May–Giemsa‐stained BM smears, by counting 500 – 2500 cells in 2 – 5 representative microscopy fields in CD138‐immunostained BM clot and biopsy sections, and CD38/CD45/CD138 gated BM PCs on flow cytometry (FCM) in 150 sets of BM samples from 120 patients. Percentages of PC were significantly correlated between BM biopsy and clot, and between smear and FCM (r = 0.96, 0.93, respectively). However, quantification by smear and FCM significantly underestimated the PC compared to biopsy or clot, and the degree of underestimation increased with blood dilution. FCM consistently showed lower % of PC compared to aspirate smears. Fifty‐nine of 103 patients with M‐protein level < 3000 mg/dL in serum or 500 mg/24 h in urine and diagnosed with monoclonal gammopathy of undetermined significance (MGUS) based on smear alone were reclassified as smoldering MM when reassessed using CD138‐stained biopsy/clot sections. Among the 72 patients with sMM diagnosed by BM biopsy and/clot, three patients (4.2%) had extensive BM infiltration of PC (≥ 60%) and required treatment. Our data clearly showed the necessity of CD138 immunostaining of BM biopsy/clot specimens for correct diagnosis of MM and related disorders. Copyright © 2016 John Wiley & Sons, Ltd.     

Monoclonal Gammopathies After Renal Transplantation: A Single-center Study

IntroductionPlasma cell disorders (PCDs) are clonal plasma cell disorders that include conditions such as monoclonal gammopathy of undetermined significance (MGUS), monoclonal gammopathy of renal significance (MGRS), multiple myeloma (MM), smoldering MM (SMM), solitary plasmacytoma, and light-chain (AL) amyloidosis. The risk factors associated with and the clinical course of PCDs after renal transplantation is not well established although immunosuppressive protocols may impact the incidence and natural history of PCDs posttransplant.Patients and MethodsThis single-center retrospective study evaluated patients with a history of renal transplant who developed a PCD between January 1, 2014-December 31, 2018.ResultA total of 41 patients met the inclusion criteria including 29 with MGUS and 12 with symptomatic PCD (4 with MM, 2 with SMM, 4 with MGRS, 1 with AL amyloidosis, and 1 with solitary plasmacytoma). The median follow-up of survivors was 41.6 months. Three patients (1 with MGUS and 2 with MGRS) progressed to MM during the follow-up period. There was a male preponderance in both groups. There was no correlation between the donor and immunosuppressive regimen and the development of a PCD. Patients with symptomatic PCD had higher serum creatinine and M-protein levels at diagnosis and higher free light chain ratio and plasma cell burden. There was also a higher percentage of allograft failure noted in the symptomatic PCD subset 50% (n = 6), whereas only 23% (n = 7) of patients had allograft failure in the MGUS group.ConclusionThis study shows the importance of considering monoclonal gammopathy in the differential of renal dysfunction after kidney transplant and the need to follow these patients closely to monitor for progression to symptomatic PCD.     

Characterization of bone marrow T cells in monoclonal gammopathy of undetermined significance, multiple myeloma, and plasma cell leukemia demonstrates increased infiltration by cytotoxic/Th1 T cells demonstrating a squed TCR-Vbeta repertoire

BACKGROUND: The majority of studies published to date regarding the role of the bone marrow (BM) microenvironment in the pathogenesis of monoclonal gammopathies (MG) have focused on the interaction between stroma cells and plasma cells, whereas information concerning the lymphocytes infiltrating the tumor microenvironment is scanty. METHODS: The authors measured the distribution, TCR-Vbeta repertoire, immunophenotype, and functional characteristics of different subsets of BM T lymphocytes from 61 nontreated patients with MG (30 patients with MG of undetermined significance [MGUS], 27 patients with multiple myeloma [MM], and 4 patients with plasma cell leukemia [PCL]). RESULTS: The authors found a significantly increased rate of BM infiltration by T cells in all patient groups, at the expense of CD4+CD8- and CD4-CD8- T lymphocytes and both CD4+CD28- and CD8+CD28- cytotoxic/effector T cell subsets, and associated with TCR-Vbeta expansions in both CD4+ and CD8+ BM T cells in the majority of patients with MGUS, MM, and PCL. Moreover, the percentage of T cells secreting interferon (IFN)-gamma was found to be increased (P < or = 0.05) both in CD4+ and CD8+ T cells in MGUS and MM patients, and a higher plasma concentration of IFN-gamma was found in patients with MM. It is interesting to note that a positive correlation was noted between the proportion of CD28- and both the percentage of IFN-gamma-secreting cells and the proportion of expanded TCR-Vbeta lymphocytes within the total BM CD4+ T cells. CONCLUSIONS: The results of the current study demonstrated an increased infiltration of BM by T cells associated with frequent TCR-Vbeta expansions and a more prominent cytotoxic/Th1 phenotype in all the patient groups studied.     

Monoclonal Gammopathy of Undetermined Significance and Smoldering Multiple Myeloma

Monoclonal gammopathy of undetermined significance (MGUS) is characterized by the presence of a serum monoclonal (M) protein level less than 3 g/dL, less than 10% clonal plasma cells in the bone marrow, and the absence of hypercalcemia, renal insufficiency, anemia, or bone lesions attributable to a clonal plasma cell disorder. Patients may be tested for a monoclonal gammopathy by serum protein electrophoresis, immunofixation, and the free light chain (FLC) assay. The prevalence of MGUS is 3% for persons more than 50 years of age and 5% in those more than 70 years of age. The risk of progression to multiple myeloma or a related disorder is 1% per year. The size and type of M protein, the number of bone marrow plasma cells, and the results of the FLC ratio are independent risk factors for progression. Smoldering multiple myeloma (SMM) is a more advanced premalignant phase than MGUS and is characterized by more than 3 g/dL of serum M protein, more than 10% clonal plasma cells in the bone marrow, or both, with no evidence of end-organ damage.     

环孢素A 抑制亲环素A 对多发性骨髓瘤细胞增殖的影响

  目的  亲环素A（cyclophilinA,CyPA）在多种肿瘤组织中高表达,在肿瘤形成发展中扮演重要的角色。本研究对CyPA在多发性骨髓瘤（multiple myeloma,MM）患者骨髓标本中的表达及其对MM细胞增殖、凋亡能力的影响进行研究,探讨其与MM发生、进展的相关性。  方法  采用ELISA法检测骨髓标本及细胞培养上清中CyPA水平。不同浓度环孢素A（cyclosporin A,CsA）刺激MM细胞,CCK-8法检测细胞增殖能力、Western blot法检测PARP蛋白裂解评价细胞凋亡水平。  结果  单克隆免疫球蛋白血症、冒烟型骨髓瘤、MM患者骨髓中CyPA浓度逐渐升高,至MM达最高值,患者治疗后CyPA浓度明显下降。CsA处理MM细胞后,CyPA分泌减少,随时间延长细胞增殖能力呈浓度依赖性逐渐减弱,PARP蛋白裂解增加、细胞凋亡增多。  结论  随MM恶性程度增加,骨髓中CyPA浓度显著升高,经治疗缓解后CyPA浓度显著下降,CyPA介导的细胞增殖在MM致癌机制中可能起关键作用。CsA作为CyPA作用的抑制剂,具有促进细胞凋亡、阻碍细胞增殖的作用,无免疫抑制作用的CsA衍生物可能是潜在的MM有效治疗手段。      

Management of monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM)

Monoclonal gammopathy of undetermined significance (MGUS) is defined as a serum M protein level of less than 3 g/dL, less than 10% clonal plasma cells in the bone marrow, and the absence of end-organ damage. The prevalence of MGUS is 3.2% in the white population but is approximately twice that high in the black population. MGUS may progress to multiple myeloma, AL amyloidosis, Waldenstr?m macroglobulinemia, or lymphoma. The risk of progression is approximately 1% per year, but the risk continues even after more than 25 years of observation. Risk factors for progression include the size of the serum M protein, the type of serum M protein, the number of plasma cells in the bone marrow, and the serum free light chain ratio. Smoldering (asymptomatic) multiple myeloma (SMM) is characterized by the presence of an M protein level of 3 g/dL or higher and/or 10% or more monoclonal plasma cells in the bone marrow but no evidence of end-organ damage. The overall risk of progression to a malignant condition is 10% per year for the first 5 years, approximately 3% per year for the next 5 years, and 1% to 2% per year for the following 10 years. Patients with both MGUS and SMM must be followed up for their lifetime.     

Prognostic factors for malignant transformation in monoclonal gammopathy of undetermined significance and smoldering multiple myeloma.

PURPOSE: To evaluate the natural history of monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM), identify early predictors of evolution, and assess whether associated conditions correlate with disease progression. PATIENTS AND METHODS: A total of 1,231 consecutive patients with either MGUS (n = 1,104) or SMM (n = 127) diagnosed from July 1975 to March 1998 were included in the study. Cumulative survival probability and cumulative probability of transformation into lymphoproliferative disease were calculated by means of the Kaplan-Meier estimator. Univariate and multivariate Cox models were used to identify possible predictors of malignant evolution. RESULTS: Cumulative transformation probability at 10 and 15 years was 14% and 30%, respectively. At a median follow-up of 65 months (range, 12 to 239 months), 64 MGUS cases (5.8%) evolved to multiple myeloma (MM) (n = 43), extramedullary plasmacytoma (n = 1), primary amyloidosis (n = 1), Waldenstr?m's macroglobulinemia (n = 12), non-Hodgkin's lymphoma (n = 6), and B-chronic lymphocytic leukemia (n = 1). At a median follow-up of 72 months (range, 12 to 247 months), 25 SMMs (19.7%) evolved to overt MM. A lower evolution risk was observed in MGUS than in SMM (P <.0001). Greater than 5% marrow plasmacytosis, detectable Bence Jones proteinuria, polyclonal serum immunoglobulin reduction, and high erythrocyte sedimentation rate (ESR) were independent factors influencing MGUS transformation. SMM progression correlated with greater than 10% marrow plasma cells, detectable Bence Jones proteinuria, and immunoglobulin (Ig) A isotype. Neither concomitant diseases nor immunosuppression correlated with progression. CONCLUSION: Careful evaluation of marrow plasmacytosis, urinary paraprotein, background immunoglobulins, ESR, and paraprotein isotype might help identify at presentation patients with benign monoclonal gammopathies requiring stricter monitoring.     

Smoldering (Asymptomatic) Multiple Myeloma: Revisiting the Clinical Dilemma and Looking Into the Future

Recent studies show that multiple myeloma (MM) is consistently preceded by an asymptomatic precursor state. Smoldering MM (SMM) is a MM precursor defined by an M-protein concentration ≥ 3 g/dL and/or ≥ 10% bone marrow plasma cells, in the absence of end-organ damage. Compared with individuals diagnosed with monoclonal gammopathy of undetermined significance (MGUS), patients with SMM have a much higher annual risk of developing MM. However, based on clinical observations, the natural history of SMM varies greatly, from stable MGUS-like disease to highly progressive disease. Using conventional clinical markers, SMM patients can be stratified into 3 risk groups. Importantly, because of considerable molecular heterogeneity, we currently lack reliable markers to predict prognosis for individual SMM patients. Furthermore, until recently, potent drugs with reasonable toxicity profiles have not been available for the development of early MM treatment strategies. Consequently, current clinical guidelines emphasize the application of close clinical monitoring followed by treatment when the patient develops symptomatic MM. This review focuses on novel biomarkers, molecular profiles, and microenvironmental interactions of interest in myelomagenesis. We also discuss how the integration of novel biologic markers and clinical monitoring of SMM could facilitate the development of early treatment strategies for high-risk SMM patients in the future.