Prognostic value of angiogenesis in solitary bone plasmacytoma

Immunoglobulin free light chains and solitary plasmacytoma of bone

An abnormal serum immunoglobulin free light chain (FLC) ratio at diagnosis may identify risk of progression to myeloma in patients with solitary bone plasmacytoma (SBP). In the cohort of 116 patients, 43 have progressed to myeloma, with a median time to progression of 1.8 years. The FLC ratio was determined in all 116 patients on serum collected at time of diagnosis and was abnormal in 54 patients (47%). An abnormal FLC ratio was associated with a higher risk of progression to myeloma (P = .039). The risk of progression at 5 years was 44% in patients with an abnormal serum FLC ratio at diagnosis compared with 26% in those with a normal FLC ratio. One to 2 years following diagnosis, a persistent serum M protein level of 5 g/L (0.5 g/dL) or higher was an additional risk factor for progression. A risk stratification model was constructed using the 2 variables of FLC ratio and M protein level: patients with a normal FLC ratio at baseline and M protein level less than 5 g/L (0.5 g/dL) at 1 to 2 years following diagnosis (low risk, n = 31); with either risk factor abnormal (intermediate risk, n = 26); and with both an abnormal FLC ratio and M protein level of 5 g/L (0.5 g/dL) or higher (high risk, n = 18). The corresponding progression rates at 5 years were significantly different in the low, intermediate, and high groups: 13%, 26%, and 62%, respectively (P < .001).

[Solitary plasmocytoma of the rib: a rare tumor not to miss]

Solitary plasmocytoma is a rare tumor accounting for 5% of all plasma cell neoplasias. The diagnosis is based on identification of the localized tumor composed of monoclonal plasma cells identical to those observed in multiple myeloma, and absence of the signs in favor of a disseminated form. We report the case of a52-year-old man who presented a growth of the chest wall in the left axillary region. Imaging disclosed a mass of tissue with a large zone of osteolysis of the 6th rib and infiltration of the chest wall. Surgical biopsy for pathology study and immunohistochemistry enabled the diagnosis of costal plasmocytoma. Blood protein immunoelectrophoresis revealed a monoclonal kappa type IgG. Bence-Jones proteinuria was positive. Search for other localizations was negative and the diagnosis of solitary plasmocytoma was retained. Radiotherapy was delivered and the patient has remained in remission at one year. Costal localization is rare for solitary plasmocytoma. The diagnosis is based on imaging findings and pathology. Radiotherapy is the treatment of choice but with the risk of progression with other bone lesions, the development of medullary plasmocytosis and multiple myeloma. Factors predictive of systemic recurrence have not been identified. Regular surveillance is required.

Prognostic factors in solitary plasmacytoma of the bone: a multicenter Rare Cancer Network study

BACKGROUND

Solitary plasmacytoma (SP) of the bone is a rare plasma-cell neoplasm. There are no conclusive data in the literature on the optimal radiation therapy (RT) dose in SP. Therefore, in this large retrospective study, we wanted to assess the outcome, prognostic factors, and the optimal RT dose in patients with SP.

METHODS

Data from 206 patients with bone SP without evidence of multiple myeloma (MM) were collected. Histopathological diagnosis was obtained for all patients. The majority (n = 169) of the patients received RT alone; 32 chemotherapy and RT, and 5 surgery. Median follow-up was 54 months (7-245).

RESULTS

Five-year overall survival, disease-free survival (DFS), and local control was 70%, 46%, and 88%; respectively. Median time to MM development was 21 months (2-135) with a 5-year probability of 51%. In multivariate analyses, favorable factors were younger age and tumor size < 5 cm for survival; younger age for DFS; anatomic localization (vertebra vs. other) for local control. Older age was the only predictor for MM. There was no dose-response relationship for doses 30 Gy or higher, even for larger tumors.

CONCLUSION

Younger patients, especially those with vertebral localization have the best outcome when treated with moderate-dose RT. Progression to MM remains the main problem. Further investigation should focus on adjuvant chemotherapy and/or novel therapeutic agents.

Monoclonal gammopathy of undetermined significance, Waldenström macroglobulinemia, AL amyloidosis, and related plasma cell disorders: diagnosis and treatment

The spectrum of plasma cell disorders is broad. Monoclonal gammopathy of undetermined significance and smoldering multiple myeloma are asymptomatic disorders characterized by monoclonal plasma cell proliferation in the bone marrow in the absence of end-organ damage. Waldenström macroglobulinemia typically involves an ontogenically less mature lymphoplasmacytic bone marrow cell and is characterized by secretion of a monoclonal IgM protein. Solitary plasmacytoma is the only known potentially curable plasma cell disorder. Finally, AL (immunoglobulin light chain) amyloidosis and POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome are disorders characterized by low tumor burden but profound multisystemic disease. Updated diagnostic criteria for these disorders, risk stratification models to determine prognosis, and the current management of these diverse entitles are discussed in this review.

Bone marrow angiogenesis in multiple myeloma

Angiogenesis is a constant hallmark of multiple myeloma (MM) progression and has prognostic potential. It is induced by plasma cells via angiogenic factors with the transition from monoclonal gammopathy of undetermined significance (MGUS) to MM, and probably with loss of angiostatic activity on the part of MGUS. The pathophysiology of MM-induced angiogenesis is complex and involves both direct production of angiogenic cytokines by plasma cells and their induction within the microenvironment. The latter are secreted by stromal cells, endothelial cells (EC) and osteoclasts, and promote plasma cell growth, survival and migration, as well as paracrine cytokine secretion and angiogenesis in the bone marrow milieu. Angiogenesis is also supported by inflammatory cells following their recruitment and activation by plasma cells. Finally, circulating EC and endothelial precursor cells (EPC) contribute to the neovascularization, and the presence of EPC suggests that vasculogenesis (new vessel formation from EPC) may also contribute to the full MM vascular tree.

Bortezomib: an effective agent in extramedullary disease in multiple myeloma

Bortezomib is a potent and selective proteasome inhibitor recently introduced in the treatment of multiple myeloma (MM). This drug produces significant responses in about one-third of patients with relapsed/refractory disease. We first recognized the lack of efficacy of thalidomide in soft-tissue plasmacytomas. There is little information on the effect of bortezomib on extramedullary myeloma. Four of 23 patients treated with bortezomib at our institution had extramedullary involvement at the time of relapse. In three of these patients large soft-tissue plasmacytomas disappeared. This indicates that bortezomib may be useful in clinical situations of extramedullary disease in which other agents, such as thalidomide, may not be effective.

Plasmacytoma relapses in the absence of systemic progression post-high-dose therapy for multiple myeloma

Autologous (ASCT) and allogeneic stem cell transplantations (alloBMT) are well-established therapies for multiple myeloma. However, patients continue to relapse at a constant rate. We present here 15 out of 163 patients who underwent SCT and relapsed with plasmacytomas only without evidence of bone marrow disease progression (14/147 post-ASCT and 1/16 post-alloBMT). The median time from SCT to plasmacytoma relapse was 24 months. The sites of plasmacytoma included bone, skin, rectum, and testicles. Five patients were treated with local radiotherapy, while seven patients received a combination of radiotherapy and chemotherapy or thalidomide, and two patients received chemotherapy alone with or without thalidomide. The recipient of alloBMT was initially treated with VAD-chemotherapy and local radiotherapy followed by a mini-allograft from the original donor. Eleven patients died at a median of 10 months following diagnosis of the plasmacytoma. Four are still alive, 12-20 months post-plasmacytoma diagnosis. These cases of unconventional disease recurrence are likely to be seen due to sub-clinical seeding of tumour cells suggestive of the presence of an extramedullary (EM) clone of plasma cells with a high degree of chemoresistance. We also review all the available data in the literature for the optimal therapy for patients with isolated EM relapse.

Plasmablastic multiple myeloma is associated with increased vascular endothelial growth factor immunoexpression

The biologic basis of the negative prognosis of plasmablastic myeloma is not fully understood. To determine whether histologically aggressive multiple myeloma (MM) is associated with a more angiogenic marrow environment, bone marrow samples from 50 recently diagnosed MM patients were evaluated. Twelve percent (6/50) of patients presented plasmablastic MM, and this feature correlated with moderate/strong intensity of vascular endothelial growth factor staining of plasma cells (P = 0.036). Although plasmablastic MM was not associated with increasing of microvessel density, this new evidence of increased expression of vascular endothelial growth factor on plasmablasts suggests that the adverse prognosis conferred by plasmablastic disease may be due, at least in part, to secretion of this angiogenic cytokine, also suggesting that the subset of MM patients with plasmablastic features may derive particular benefit from antiangiogenic therapies.

Outcomes and patterns of failure in solitary plasmacytoma: a multicenter Rare Cancer Network study of 258 patients

PURPOSE

To assess the outcomes and patterns of failure in solitary plasmacytoma (SP).

METHODS AND MATERIALS

The data from 258 patients with bone (n = 206) or extramedullary (n = 52) SP without evidence of multiple myeloma (MM) were collected. A histopathologic diagnosis was obtained for all patients. Most (n = 214) of the patients received radiotherapy (RT) alone; 34 received chemotherapy and RT, and 8 surgery alone. The median radiation dose was 40 Gy. The median follow-up was 56 months (range 7-245).

RESULTS

The median time to MM development was 21 months (range 2-135), with a 5-year probability of 45%. The 5-year overall survival, disease-free survival, and local control rate was 74%, 50%, and 86%, respectively. On multivariate analyses, the favorable factors were younger age and tumor size <4 cm for survival; younger age, extramedullary localization, and RT for disease-free survival; and small tumor and RT for local control. Bone localization was the only predictor of MM development. No dose-response relationship was found for doses >30 Gy, even for larger tumors.

CONCLUSION

Progression to MM remains the main problem. Patients with extramedullary SP had the best outcomes, especially when treated with moderate-dose RT. Chemotherapy and/or novel therapies should be investigated for bone or bulky extramedullary SP.

Cytokines and signal transduction

Many studies have characterized the role of growth factors in multiple myeloma (MM) pathogenesis and have derived novel therapies to improve patient outcome based upon targeting cytokines and their signaling cascades both in the MM cell and in the bone-marrow (BM) microenvironment. These cytokines include interleukin 6 (IL-6), insulin-like growth factor 1 (IGF-1), vascular endothelial growth factor (VEGF), tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta (TGF-beta), stromal cell-derived factor 1alpha (SDF-1alpha), IL-21, B-cell stimulating factor 3 (BSF-3) and fibroblast growth factor (FGF). These cytokines are secreted from stromal cells (SCs), endothelial cells and/or osteoclasts, and promote MM cell growth, survival and migration, as well as paracrine cytokine secretion and angiogenesis in the BM milieu. Thus inhibition of signaling cascades induced by these cytokine provides rationale for a therapeutic option for MM.

CD45 expression by bone marrow plasma cells in multiple myeloma: clinical and biological correlations

Multiple myeloma (MM) is characterized by accumulation of clonal plasma cells (PCs). CD45, a key regulator of antigen-mediated signaling and activation in lymphocytes, is present in early stages of PCs development. We studied CD45 expression on MM PCs by flow cytometry, correlating it to important biological disease characteristics. Additionally, we examined the expression of various adhesion molecules on PCs. A total of 75 patients with untreated MM (29), relapsed MM (17), smoldering MM (12), and monoclonal gammopathy of undetermined significance (MGUS) (17) were studied. The proportion of PCs expressing CD45 was higher among those with early disease (MGUS or smoldering MM) compared to those with advanced disease (new or relapsed MM) (43 vs 22%; P=0.005). Among those with advanced disease, patients with bone lesions had a lower percentage of CD45-positive (CD45+) PCs; 14 vs 34% (P=0.02). Patients with high-grade angiogenesis had a lower percentage of CD45+ PCs; 13 vs 31% (P=0.03). The median overall survival for the CD45+ group (>20% PCs positive) was 39 vs 18 months for the CD45-negative (CD45-) group (P=0.07). The expression of CD138, CD56 and CD54 were higher among the CD45- PCs. This study demonstrates important biological correlates of CD45 expression on myeloma cells.

p16 gene methylation lacks correlation with angiogenesis and prognosis in multiple myeloma

Methylation of p16 gene is a relatively frequent molecular finding in multiple myeloma (MM), but its clinical implication is disputable. Cell cycle regulators are now recognized as active in the control of angiogenesis, which is an integral component of pathogenesis and a target for new treatment modalities of this disease. On such background, we focused on determining whether loss of p16 function by methylation could be associated with increased angiogenesis and VEGF expression, and the prognostic relevance of p16 methylation in 50 untreated, newly diagnosed MM patients. Thirty-one percent (13/42) of 42 patients assessable for p16 gene methylation showed to be methylation-positive. High-angiogenesis was present in 73% of cases, but methylation of the p16 gene did not associate with angiogenesis or with VEGF expression. Also, p16 methylation did not show prognostic relevance or correlation with the clinical and laboratory parameters of prognostic significance in univariate analysis. P16 immunoexpression presented only a faint agreement with the molecular study. Therefore, p16 methylation seems to have no correlation with angiogenesis and VEGF expression, neither with overall and event-free survival in MM patients. Besides, P16 immunohistochemistry seems inadequate to substitute the molecular study of methylation in this type of tumor cells. Additional studies are needed to clarify the correspondence between the epigenetic alteration of the p16 gene and its protein immunexpression, and the clinical relevance of p16 methylation in MM patients.

MGUS and Smoldering Multiple Myeloma: Update on Pathogenesis, Natural History, and Management

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic, pre-malignant disorders characterized by monoclonal plasma cell proliferation in the bone marrow and absence of end-organ damage. Recent advances in the pathogenesis, natural history, and prognosis of MGUS and SMM are reviewed. A new risk stratification system to determine the prognosis of MGUS using the size and type of M protein, and the serum free light chain assay is discussed.

Prognostic significance of vascular endothelial growth factor immunoexpression in the context of adverse standard prognostic factors in multiple myeloma

OBJECTIVES

Vascular endothelial growth factor (VEGF) acts in several steps of multiple myeloma (MM) pathogenesis and it is an important mediator of tumor angiogenesis. The aim of this study was to examine the prognostic significance of VEGF immunoexpression in the context of standard prognostic factors present in a cohort of advanced MM patients.

METHODS

Fifty untreated MM patients were enrolled from May 2000 to December 2002. Bone marrow sections were subjected to morphologic assessment and immunohistochemical studies with antibodies against CD34 and VEGF. Angiogenesis was measured by microvessel density (MVD) and stratified into high (MVD > or = 20) and low angiogenesis status (MVD < 20). VEGF immunoreactivity was examined on the basis of intensity and percentage of positive plasma cells (PC).

RESULTS

Ninety-four percent of patients presented advanced disease at diagnosis. Median PC marrow infiltration was 80%. Twelve percent of patients presented plasmablastic morphology. Low angiogenesis was present in 27% of patients, while high angiogenesis was present in 73%. Twenty-nine percent of patients had VEGF < 10% and 71% had VEGF > or = 10%. Weak-intensity VEGF was observed in 34% of cases, while 37% had moderate/strong VEGF intensity. Although VEGF had prognostic impact on overall survival (OS) and event-free survival (EFS) in univariate analysis, multivariate analysis identified only plasmablastic morphology and elevated serum lactate dehydrogenase (LDH) level as independent prognostic factors to predict OS (P = 0.04 and P = 0.02, respectively). With regard to EFS, although VEGF showed statistical trend to influence survival (P = 0.08), the parameters of independent prognostic value were also plasmablastic morphology (P = 0.01) and elevated LDH level (P = 0.01).

CONCLUSION

Our findings underline the frequent expression of VEGF in advanced-stage MM and the greater prognostic information of simple and readily available factors, namely plasmablastic morphology and elevated LDH. Moreover, despite the absence of prognostic importance in multivariate analysis, VEGF and its receptors remain promising therapeutic targets in MM.

The pathophysiologic role of VEGF in hematologic malignancies: therapeutic implications

Besides its role as an essential regulator of physiologic and pathologic angiogenesis, vascular endothelial growth factor (VEGF) triggers growth, survival, and migration of leukemia and multiple myeloma cells; plays a pivotal role in hematopoiesis; inhibits maturation of dendritic cells; and increases osteoclastic bone-resorbing activity as well as osteoclast chemotaxis. Dysregulation of VEGF expression and signaling pathways therefore plays an important role in the pathogenesis and clinical features of hematologic malignancies, in particular multiple myeloma. Direct and indirect targeting of VEGF and its receptors therefore may provide a potent novel therapeutic approach to overcome resistance to therapies and thereby improve patient outcome.

Prognostic value of bone marrow angiogenesis in patients with multiple myeloma undergoing high-dose therapy

Bone marrow (BM) angiogenesis is increased in multiple myeloma and is an important prognostic factor. However, prior studies were mainly done on patients receiving conventional chemotherapy and there is limited data on its prognostic value in patients undergoing high-dose therapy (HDT) as initial therapy. We studied BM angiogenesis in terms of microvessel density (MVD) in 88 newly diagnosed patients, who were uniformly treated, with 3-4 cycles of induction chemotherapy followed by HDT. We examined if MVD at diagnosis was predictive of response to induction therapy or to subsequent HDT. In addition, we also examined its prognostic value in these patients. The median MVD for primary refractory patients was 28 (range, 2-84) compared to 27 (range, 2-99) for responding patients (P=0.7). The median progression-free survival (PFS) was 21 months for those with high-grade angiogenesis compared to 42 months for those with low-grade angiogenesis, P=0.017. The median overall-survival (OS) from diagnosis was 40 months for those with high-grade angiogenesis and not yet reached, for those with low-grade angiogenesis, P=0.007. BM MVD at the time of initial diagnosis is an important prognostic factor for OS and PFS in patients undergoing autologous transplantation as frontline therapy for myeloma.

Bone marrow angiogenic ability and expression of angiogenic cytokines in myeloma: evidence favoring loss of marrow angiogenesis inhibitory activity with disease progression

We compared the angiogenic potential of bone marrow plasma and the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors on plasma cells from patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and newly diagnosed multiple myeloma (NMM). Cytokine and cytokine-receptor expression was studied by bone marrow immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (RT-PCR) on sorted plasma cells, and quantitative Western blot analysis. Bone marrow angiogenic potential was studied using a human in vitro angiogenesis assay. The expression levels of VEGF, bFGF, and their receptors were similar among MGUS, SMM, and NMM. Sixty-one percent of NMM samples stimulated angiogenesis in the in vitro angiogenesis assay compared with SMM (0%) and MGUS (7%) (P <.001). Importantly, 63% of MGUS samples inhibited angiogenesis compared with SMM (43%) and NMM (4%) (P <.001). The inhibitory activity was heat stable, not overcome by the addition of VEGF, and corresponded to a molecular weight below 10 kd by size-exclusion chromatography. Our results suggest that increasing angiogenesis from MGUS to NMM is, at least in part, explained by increasing tumor burden rather than increased expression of VEGF/bFGF by individual plasma cells. The active inhibition of angiogenesis in MGUS is lost with progression, and the angiogenic switch from MGUS to NMM may involve a loss of inhibitory activity.

Angiogenic switch during 5T2MM murine myeloma tumorigenesis: role of CD45 heterogeneity

The active role of angiogenesis during disease progression is well recognized in solid tumors. In hematologic malignancies such as multiple myeloma (MM), it is not known whether tumor neovascularization is an epiphenomenon or whether it is actively involved in disease progression. At clinical presentation, myeloma disease and the associated angiogenesis are both well established. Here the 5T2MM murine model was used to analyze angiogenesis during preclinical myeloma stages. Bone marrow (BM) of 5T2MM-inoculated mice was analyzed at weekly intervals until the end stage of the disease. Histologic analysis and assessment of microvessel density (MVD) by CD31 staining demonstrated a preangiogenic stage of small tumor aggregates followed by an angiogenic switch and subsequently an angiogenic stage of progressive tumor growth and large, confluent tumor nodules. Flow cytometric analysis that indicated an increase in percentage CD45- MM cells preceded the angiogenic switch. Real-time polymerase chain reaction (RT-PCR) of sorted CD45+ and CD45- MM cells indicated higher vascular endothelial growth factor 120 (VEGF120) and VEGF164 transcripts in CD45- MM cells. VEGF enzyme-linked immunosorbent assay (ELISA) revealed high secretion by CD45- MM cells but no protein secretion by CD45+ MM cells, indicating angiogenic heterogeneity among the MM cells. These data suggest that, like in solid tumors, angiogenic switch and angiogenic heterogeneity exist in MM.

Angiogenesis in Waldenstrom's macroglobulinemia

Angiogenesis has been associated with disease progression and poor prognosis in several hematologic malignancies including multiple myeloma. In this article, we summarize the rationale for studying angiogenesis in plasma cell disorders including Waldenstrom's macroglobulinemia (WM). We also discuss the results of a study of angiogenesis in WM conducted at the Mayo Clinic. Our study shows that only 30% of patients with WM had increased (intermediate- or high-grade) angiogenesis. A weak correlation was found between mean microvessel density (MVD) and marrow infiltration. Unlike multiple myeloma, MVD and angiogenesis grade were not predictive factors for survival. Although these findings suggest that angiogenesis may not be a major factor in WM, it does not exclude a paracrine role for angiogenic cytokines or the study of antiangiogenic agents in this disease.