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Bone marrow (BM) angiogenesis significantly influences disease progression in multiple myeloma (MM) patients and correlates with adverse prognosis. The present study shows a statistically significant correlation of the AP-1 family member JunB with VEGF, VEGFB, and IGF1 expression levels in MM. In contrast to the angiogenic master regulator Hif-1α, JunB protein levels were independent of hypoxia. Results in tumor-cell models that allow the induction of JunB knockdown or JunB activation, respectively, corroborated the functional role of JunB in the production and secretion of these angiogenic factors (AFs). Consequently, conditioned media derived from MM cells after JunB knockdown or JunB activation either inhibited or stimulated in vitro angiogenesis. The impact of JunB on MM BM angiogenesis was finally confirmed in a dynamic 3D model of the BM microenvironment, a xenograft mouse model as well as in patient-derived BM sections. In summary, in continuation of our previous study (Fan et al., 2017), the present report reveals for the first time that JunB is not only a mediator of MM cell survival, proliferation, and drug resistance, but also a promoter of AF transcription and consequently of MM BM angiogenesis. Our results thereby underscore worldwide efforts to target AP-1 transcription factors such as JunB as a promising strategy in MM therapy., (© 2021. The Author(s).)

Angiogenesis is a constant hallmark of multiple myeloma (MM) progression and involves direct production of angiogenic cytokines by plasma cells and their induction within the bone marrow microenvironment. This article summarizes the more recent literature data concerning the employment of anti-angiogenic therapeutic agents actually used in preclinical models and clinical settings for the treatment of multiple myeloma.

Increasing evidences suggest several biological roles for erythropoietin and its receptor (Epo and EpoR), unrelated to erythropoiesis, including angiogenesis. Here, we detected the expression of EpoR in bone marrow-derived endothelial cells from monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) patients (MGECs and MMECs, respectively) and assessed whether Epo plays a role in MGECs- and MMECs-mediated angiogenesis. We show that EpoR is expressed by both MGECs and MMECs even though at a higher level in the first ones. Both EC types respond to rHuEpo in terms of cell proliferation, whereas other responses, including activation of JAK2/STAT5 and PI3K/Akt pathways, cell migration and capillarogenesis are enhanced by Epo in MGECs, but not in MMECs. In addition, the conditioned media of both Epo-treated cells induce a strong angiogenic response in vivo in the chorioallantoic membrane assay, comparable to that of vascular endothelial growth factor (VEGF). Overall, these data highlight the effect of Epo on MGECs- and MMECs-mediated angiogenesis: MGECs are more responsive to Epo treatment than MMECs, probably because over-angiogenic phenotype of MMECs is already activated by their autocrine/paracrine loops occurring in the "angiogenic switch" from MGUS.

Purpose: The aim of the present study was to evaluate CD105 tissue marker in the bone marrow (BM) of multiple myeloma (MM) patients. CD105 was evaluated using immunohistochemical method. An effort was made to correlate this marker with BM microvascular density (MVD) along with other known markers of angiogenesis in order to evaluate its clinical significance., Methods: BM MVD was estimated by CD31. CD105 in BM was estimated by immunohistochemical method in 54 newly diagnosed patients with MM. Circulating levels of known angiogenic factors such as basic fibroblast growth factor (b-FGF) and soluble CD105 (sCD105) were measured by ELISA in the same group of patients. All these factors were also measured in 20 age- and sex-matched healthy controls., Results: We found that CD105 MVD, along with the expected CD31 MVD, and serum levels of sCD105 and bFGF were increased, also in parallel with disease stage, and all were decreased after effective treatment. Moreover, CD105 MVD correlated with all the aforementioned markers of angiogenesis., Conclusions: Our results indicated that CD105 MVD is following the behavior of CD31 MVD in MM, suggesting being a valid marker of BM neoangiogenesis in MM. Its prognostic impact remains to be proven.

The ability to characterize distribution of neoplastic hematopoietic cells and their progenitors in their native microenvironment is emerging as an important challenge and potential therapeutic target in many disease areas, including multiple myeloma. In multiple myeloma, bone marrow (BM) angiogenesis is typically increased and microvessel density is a known indicator of poor prognosis. However, the difficulty of consistently measuring 3D vessels from 2D cut sections has previously limited the study of spatial distribution of plasma cells (PC) and their interaction with BM microenvironment. The aim of the study is to report a novel method to study myeloma cells spatial distribution within their hematopoietic niche context using readily available tissue sections and standard histology approaches. We utilized a novel whole-tissue image analysis approach to identify vessels, and then applied computational grown regions extended out from each vessel at 15, 35, 55, 75, and 100 μm to identify the spatial distribution of PC on CD34/CD138 double-stained core biopsy slides. Percent PC to total cells (TC) was significantly higher at <15 μm distance compared with those at 16 to 35, 36 to 55, 56 to 75, and 76 to 100 μm distance (P=0.0001). Similarly, PC/TC at <35 μm region was significantly higher compared with 36 to 55 (P=0.0001), 56 to 75 (P≤0.0001), and 76 to 100 (P=0.0002) μm distances. The mean PC/TC differences in the spatial gradient of 36 to 55, 56 to 75, and 76 to 100 μm distance regions were not significant. Our findings suggest possible preferential advantage to neoplastic PC in the proximity of blood vessels compared with other hematopoietic marrow cells. We demonstrate the feasibility of analyzing the spatial distribution of PC, and possibly other hematopoietic/stem cells in their microenvironment, as characterized by the distance to vessels in BM using a novel image analysis approach.

Angiogenesis is a constant hallmark of multiple myeloma progression and has prognostic potential. Multiple myeloma cells interact with surrounding host cells and extracellular matrix, this crosstalk affecting the most important aspects of the malignant phenotype, both at primary and secondary tumor sites. The pathophysiology of multiple myeloma-induced angiogenesis involves both direct production of angiogenic cytokines by plasma cells and their induction within the bone marrow microenvironment cells. A direct involvement of bone marrow macrophages and mast cells in vasculogenic mimicry has been demonstrated, thus contributing together with circulating endothelial cells and endothelial precursor cells to the multiple myeloma neovascularization. The role of host cells or the niche microenvironment and extracellular matrix represents an intense area of research, finalized at a better understanding of the pathophysiological modifications of the complete tumor entity, i.e. malignant cells and microenvironment., (Copyright © 2014 S. Karger AG, Basel.)

Bone marrow contains hematopoietic stem cells (HSCs) and non hematopoietic cells. HSCs are able to give rise to all types of mature blood cells, while the non hematopoietic component includes osteoblasts/osteoclasts, endothelial cells, endothelial progenitor cells and mesenchymal stem cells. All of these cells form specialized "niches" which are close to the vasculature ("vascular niche") or to the endosteum ("osteoblast niche"). The "vascular niche" is rich in blood vessels where endothelial cells and mural cells (pericytes and smooth muscle cells) create a microenvironment that affects the behavior of several stem and progenitor cells. The vessel wall serves as an independent niche for the recruitment of endothelial progenitor cells, mesenchymal stem cells and HSCs. The activation by angiogenic factors and inflammatory cytokines switch of the "vascular niche" promote tumor growth. This review article will focus on the description of the mechanisms involved in the generation of signals released by endothelial cells in the "vascular niche" that promote tumor growth in multiple myeloma.

In multiple myeloma (MM), angiogenesis plays a substantial role in disease progression. Interleukin-8 (IL-8), a pro-inflammatory chemokine with potent pro-angiogenic properties, has been implicated in the pathophysiology of MM. The aim of the study is to measure serum levels of IL-8 in MM patients and to correlate them with markers of angiogenesis, such as circulating levels of platelet derived growth factor-AB (PDGF-AB) and angiogenin (Ang), and bone marrow microvascular density (MVD). Fifty-three newly diagnosed MM patients, 23 of them, who reached plateau phase after effective treatment and 20 healthy controls, were studied. Serum levels of PDGF-AB, Ang and IL-8 were measured by ELISA, whereas bone marrow MVD was estimated by immunohistochemical staining of vessels with anti-CD31. All measured parameters were higher in MM patients compared to controls and in increased disease stages. They all also significantly decreased in plateau phase. IL-8 correlated positively with Ang and PDGF-AB, but not with MVD. The circulating levels of IL-8, PDGF-AB and Ang are elevated in patients with MM. The lack of correlation between IL-8 with MVD suggests that its levels represent the inflammatory element of MM disease and the participation in angiogenesis process is rather complex with multifactorial mechanisms.

The aim of our study was to emphasize the importance of accurate and standardized techniques for detailed monitoring of the microenvironment in multiple myeloma (MM). Bone marrow fibrosis, angiogenesis, and plasma cell infiltrates in bone marrow biopsy (BMB) samples at the time of diagnosis and on completion of therapy were analyzed for 42 patients with newly diagnosed MM. Computerized image analysis was used for all slides stained with anti-CD138 and anti-CD34. The patients with fibrosis in pretreatment BMB samples had significantly higher microvessel density (MVD) and plasma cell infiltrates. In posttreatment BMB samples, nonresponders had a significantly higher frequency and grade of fibrosis and higher values of MVD, total vascular area, and plasma cell percentage. The overall survival of nonresponders and patients with increased marrow fibrosis in posttreatment BMB samples was significantly shorter. The obtained results confirm that complex morphologic examination of the bone marrow microenvironment during the monitoring of MM can provide better prognostic significance.

Purpose: The aim of our study was to investigate whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) allows visualization of changes in microcirculation between healthy controls on the one side and early/advanced stages of plasma cell disease on the other., Experimental Design: We examined a group of 222 individuals consisting of 60 patients with monoclonal gammopathy of undetermined significance (MGUS), 65 patients with asymptomatic multiple myeloma (aMM), 75 patients with newly diagnosed symptomatic MM (sMM), and 22 healthy controls with DCE-MRI of the lumbar spine., Results: A continuous increase in microcirculation parameters amplitude A and exchange rate constant kep reflecting vascular volume and permeability, respectively, was detected from normal controls over MGUS and aMM to sMM. For A and kep, significant differences were found between controls and aMM (P = 0.03 and P = 0.004, respectively) as well as controls and sMM (P = 0.001 and P < 0.001, respectively). Although diffuse microcirculation patterns were found in healthy controls as well as MGUS and MM, a pattern with focal hotspots was exclusively detected in 42.6% of sMM and in 3 MGUS and 3 aMM patients. MGUS and aMM patients with increased microcirculation patterns showed significantly higher bone marrow plasmocytosis compared with patients with a low microcirculation pattern., Conclusions: Our investigations substantiate the concept of an angiogenic switch from early plasma cell disorders to sMM. Pathologic DCE-MRI findings correlate with adverse prognostic factors and DCE-MRI identifies a distinct group of patients with increased microcirculation parameters in aMM and MGUS patients.

We studied the prognostic value of parameters of angiogenesis on bone marrow biopsies in newly diagnosed multiple myeloma (MM) patients. Angiogenesis parameters studied were the microvessel count done manually on light microscopy (MVD-A), microvessel count done by using computerized image analyzer (MVD-B), and total vascular area (TVA) measured by computerized image analyzer. One hundred ten newly diagnosed cases of MM treated at Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, were analyzed with respect to clinical features, laboratory findings, histological features, angiogenesis parameters, and responses to the treatment on follow-up. Twenty age- and sex-matched controls were studied for comparing with angiogenesis of the test cases. Bone marrow microvessels were examined using immunohistochemical staining for CD34. MVD-A (range 4.9-85.2; mean 28.2; SD 19.4), MVD-B (range 2.0-26.9; mean 11.7; SD 5.9), and TVA measured in percentage (range 0.1-17.1; mean 2.4; SD 2.5) were measured for test cases (n = 110). Grading of angiogenesis parameters of the test cases were done; such that angiogenesis parameters of controls (taken as baseline) were grade I. There was a statistically highly significant correlation between (MVD-A vs MVD-B, pcc = 0.92; MVD-A vs TVA, pcc = 0.78; MVD-B vs TVA, pcc = 0.76). The myeloma cases had significantly higher angiogenesis parameters when compared with controls (Kruskall-Wallis test, P < 0.001). "Complete responders" (n = 38/110) had significant lower angiogenesis (Mann-Whitney U test, P < 0.001) than "nonresponders" (n = 72/110). On treatment follow-up "rapid disease progressors" had the highest levels of angiogenesis (mean rank for MVD-A = 84.7, MVD-B = 82.1, and TVA = 81.1). On multivariate (logistic regression) analysis, factors found to have independent prognostic significance in complete responders (adjusted odd ratio (95% CI, P value)] were: (a) MVD-B grade I [0.134 (0.10-0.16, P < 0.001)], (b) clinical substage A [0.163 (0.12-0.19, P = 0.008)], (c) Bartl's histological stage II & I [0.262 (0.2-0.32, P = 0.021)], (d) MVD-A grade I [0.28 (0.22-0.36, P = 0.03)], (e) beta2 microglobulin levels less than 3,400 ng/dl [0.31 (0.23-0.42, P = 0.04)]. Kaplan-Meier survival analysis for myeloma-related death (n = 16) shows a mean survival time (in months) of 24.75; SE = 3; 95% CI = 21-28. We conclude that MVD (particularly MVD-B) is a very good predictor for the complete response in patients of MM and should be done routinely on bone marrow biopsies., ((c) 2006 Wiley-Liss, Inc.)

Multiple myeloma (MM) was the first haematological malignancy in which a prognostic relevance of bone marrow microvessel density (MVD) was shown. Myeloma-induced angiogenesis involves either the direct production of angiogenic molecules by myeloma cells or their induction in bone marrow stromal cells or endothelial cells (EC). Recent data demonstrate an increased angiogenic potential and a paracrine stimulatory effect of bone marrow EC on plasma cells (PC) in MM. Soluble angiogenic factors are elevated in bone marrow (BM) and in peripheral blood samples from myeloma patients. Furthermore, correlation with disease stage and prognosis was shown for serum levels of the angiogenic factors basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF). In this review we summarize recent data which give strong evidence for an increased angiogenic activity in bone marrow microenvironment and support the hypothesis that angiogenesis is not only an epiphenomenon of tumour growth but may also promote PC growth in MM.

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.

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.

Increased microvessel density (MVD) has been observed in the bone marrow (BM) of patients with multiple myeloma (MM), acute lymphoblastic leukaemia, acute myeloid leukaemia, and myelodysplastic and myeloproliferative syndrome. The MVD is the net result of cumulative phases of angiogenesis and angio-regression and is as such not an indicator of the ongoing angiogenesis at the time of biopsy. There is, therefore, a need for additional methods that allow the estimation of ongoing angiogenesis. Double immunostainings for CD34 and Ki-67 can be used on paraffin-embedded tissue to determine the endothelial proliferation fraction. The BM endothelial cells, as a component of the BM stroma, have a close interaction with the malignant cells. In MM, for example, they are involved in the specific homing and are a source of paracrine growth factors. Targeting the BM microvessels will not only influence the nutrient and oxygen supply, but will in addition reduce the growth stimuli provided by the EC.

There is evidence that angiogenesis plays an important role in the progression of multiple myeloma (MM). Hepatocyte growth factor (HGF) and tumor necrosis factor-alpha (TNF-alpha) are cytokines that potently stimulate angiogenesis. We evaluated the microvascular density (MVD) of bone marrow biopsies (after immunostaining with anti-CD34 antibodies) and serum levels of HGF and TNF-alpha in 43 patients with newly diagnosed MM. Twenty-four of these patients reached a plateau phase after treatment and were reevaluated for MVD, HGF and TNF-alpha. MVD values and serum levels of HGF and TNF-alpha were elevated in newly diagnosed MM patients in comparison with healthy controls. Pre-treatment MVD, HGF and TNF-alpha increased with advancing stage of MM disease. In patients reaching the plateau phase, a significant reduction in MVD, HGF and TNF-alpha levels occurred. A positive correlation was noted between pre-treatment MVD and serum levels of TNF-alpha and lactic dehydrogenase but not with HGF. However, HGF strongly correlated with beta2-microglobulin (beta2M), TNF-alpha and lactate dehydrogenase (LDH). We conclude that angiogenesis in MM, as expressed by the bone marrow MVD and the serum levels of angiogenic molecules such as HGF and TNF-alpha, increases with advancing clinical stage and decreases after effective chemotherapy.

The expression of proliferating cell nuclear antigen (PCNA) was studied in plasma cells in bone marrow biopsies from patients with multiple myeloma (MM) using a double immunostaining method. In the same samples, microvessel density (MVD), after staining with anti-CD34 antibodies, was determined before and after chemotherapy. The correlation of PCNA expression and MVD with other myeloma parameters (clinical stage, bone marrow plasma cell infiltration and serum interleukin-6 (IL-6)) was also investigated. The study population included 51 newly diagnosed MM patients, 15 patients in plateau phase after treatment and 15 normal controls. Pretreatment mean +/- SE values of PCNA, MVD, plasma cell infiltration and serum IL-6 were significantly higher than post treatment values and controls. Pretreatment PCNA expression correlated significantly with bone marrow MVD (p<0.05) plasma cell infiltration (p<0.01) and IL-6 (p<0.01). These findings show that the proliferative activity of plasma cells is related to the angiogenic activity in the bone marrow of multiple myeloma patients. Both PCNA and MVD correlate with markers of disease activity thus may provide additional information when included in the initial evaluation of myeloma bone marrow biopsies.

Endothelial cells (EC) were extracted through a lectin-based method from bone marrow of 57 patients with active multiple myeloma (MM) and compared with their healthy quiescent counterpart, human umbilical vein EC (HUVEC). MMECs exhibit specific antigens that indicate ongoing angiogenesis and embryo vasculogenesis; solid intercellular connections, hence stability of MM neovessels; and frequent interactions with plasma cells, hence tumor dissemination. They show heterogeneous antigen expression, hence existence of subsets. Their main genetic markers are indicative of a vascular phase. They show intrinsic angiogenic ability, because they rapidly form a capillary network in vitro, and extrinsic ability, because they generate numerous new vessels in vivo. They vividly secrete growth and invasive factors for plasma cells. They signal through kinases mandatory for development of neovascularization. Ultrastructurally, they are abnormal and show metabolic activation, like tumor ECs. Thalidomide heavily interferes with their functions. Vasculogenesis and angiogenesis might contribute to the MM vascular tree and progression, in the form of growth, invasion, and dissemination. In view of the heterogeneity of the antigenic phenotype of MMECs, a mixture (or a sequence) of antiangiogenic agents coupled with thalidomide would seem plausible for the biologic management of MM.

Solid organ tumors associated with neoangiogenesis, as measured by increased microvessel density (MVD), have poorer prognoses. A similar observation of increased MVD has been made in hematologic malignancies; however, its prognostic significance remains unknown. We investigated changes in MVD in 122 newly diagnosed multiple myeloma patients uniformly treated according to the "Total Therapy" protocol (remission induction followed by tandem autotransplants and interferon maintenance) from a set of 231 patients. MVD was measured as mean of 10 fields (MVD) and the single highest field (SHF) on anti-CD34-stained Zenker-fixed paraffin-embedded bone marrow biopsy sections at 400x magnification. MVD was markedly elevated in this population, with a median of 4.4 vessels/field (range, 0.6 to 55.7), and SHF was 13 vessels/field (range, 2 to 80). When compared to 54 patients with less than 4 MVD, 67 patients with mean MVD of greater than 4 had a significantly inferior median duration of event-free survival (EFS) (2.7 v 4.3 years; P =.03), overall survival (OS) (4.3 v 7.9+ years, P =.006), and median complete response (CR) duration (2.2 v 6.8+ years, P=.003). A similarly significant unfavorable relationship to EFS and OS was present for SHF greater than 13. On multivariate analysis of other previously recognized prognostic factors (beta(2)-microglobulin [beta2M], C-reactive protein [CRP], and Bartl grade; and deletion 13), MVD < or = 4 emerged as a major favorable prognostic variable for OS followed by CRP < or = 4, P=.006. Thus, tumor-associated angiogenesis as reflected by MVD is a biologically relevant and important prognostic feature that can be targeted by antiangiogenesis therapy such as thalidomide, which has remarkable antitumor activity in advanced and refractory multiple myeloma., (Copyright 2001 by W.B. Saunders Company.)

Angiogenesis is the process of new blood vessel formation, and normally occurs during embryonal growth, wound healing, and the menstrual cycle. It is essential for the proliferation and metastases of most malignant neoplasms. There is now growing evidence that angiogenesis is increased and is likely important in multiple myeloma. Recent evidence suggests that angiogenesis is greater in multiple myeloma compared to monoclonal gammopathy of undetermined significance (MGUS). Angiogenic cytokines such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are expressed by neoplastic plasma cells, and may play a role in the increased angiogenesis seen in myeloma. In a study of 400 patients with plasma cell disorders, microvascular density (MVD) was significantly higher in smoldering myeloma, newly diagnosed myeloma, and relapsed myeloma compared to controls, MGUS, and primary amyloidosis. In another study involving 74 newly diagnosed patients with myeloma treated at the Mayo Clinic, overall survival was significantly longer in patients with low-grade angiogenesis compared to those with high-grade or intermediate-grade angiogenesis. The finding of increased angiogenesis in myeloma provides the rationale for the study of antiangiogenic therapy in this disease., (Copyright 2001 by W.B. Saunders Company.)

Factor VIII-related antigen (FVIII-RA)-positive microvessel areas were measured by both immunohistochemistry and computerized image analysis in patients with active multiple myeloma (MM), nonactive MM, and monoclonal gammopathies of undetermined significance (MGUS). A five-to sixfold larger area was found in patients with active MM compared to the other two groups. Aquaporin 1 (AQP1)-positive microvessel areas, measured with the same techniques on adjacent tissue sections, were also increased in active MM, and tended to be larger than and closely correlated with the FVIII-RA areas. Numerous mast cells were found in the bone marrow of active MM patients, and counts were strictly correlated with the microvessel density. The conditioned medium (CM) of bone marrow plasma cells from active MM patients stimulated endothelial cell proliferation and chemotaxis, monocyte chemotaxis, and angiogenesis in vivo (assessed by the chick embryo chorioallantoic membrane [CAM] system) more strongly and frequently than the CM of patients with nonactive MM and MGUS. Immunoassay of plasma cell lysates gave significantly higher levels of fibroblast growth factor-2 (FGF-2) in patients with active MM than in the other two groups, and a neutralizing anti-FGF-2 antibody inhibited by 46% to 68% the biological activity exerted by the CM in vitro and in the CAM. In situ hybridization of bone marrow plasma cells and zymography of CM showed that patients with active MM express higher levels of matrix metalloproteinase-2 (MMP-2) mRNA and protein than those with nonactive MM and MGUS, whereas MMP-9 expression and secretion overlapped in all groups. Overall data indicate that patients with active MM represent the vascular phase of plasma cell tumors that is induced, at least partly, through FGF-2 and MMP-2. Mast cells possibly contribute to the vascular phase via angiogenic factors in their secretory granules. Both angiogenesis and MMP-2 secretion can account for intramedullary and extramedullary spreading of plasma cells in patients with active MM., (Copyright 2001 by W.B. Saunders Company.)

The impact of angiogenesis is well known for the growth and viability of solid tumors. Fewer studies have been published relating angiogenesis to clinical or pathological parameters in hematological malignancies. In this report, we have estimated the bone marrow microvessel density (MVD) before and after conventional-dose or high-dose chemotherapy with autologous stem cell transplantation. Immunohistochemical CD34-stained paraffin-embedded bone marrow biopsies of 21 patients with stage III multiple myeloma were studied. Microvessels were counted at 400x magnification, and the mean number of vessels per area in each sample was noted as the MVD. The median MVD of all patients was 53.1 vessels/mm2 (range 15.5-174.7 vessels/mm2) before treatment and 29.3 vessels/mm2 (range 0-221.1 vessels/mm2) after chemotherapy. The post-treatment MVD in the two groups of patients with and without remission was significantly different (p=0.001), whereas the pretreatment MVD was not. Responders but not nonresponders showed a significant decrease of MVD after therapy in comparison to their pretreatment levels. The progression-free survival in patients who achieved a reduction in MVD after chemotherapy was significantly longer than in patients without a decrease in MVD (P=0.006). Furthermore, we compared the MVD of patients after achievement of a remission to MVD of 15 untreated stage I myeloma patients. The MVD of patients in remission was not statistically different from the MVD in stage I myeloma. These results underscore the impact of angiogenesis in myeloma and give the first report that effective chemotherapy is accompanied by a significant decrease in bone marrow angiogenesis in this disease.

We studied the prognostic value of angiogenesis grading and microvessel density estimation in newly diagnosed multiple myeloma. Seventy-five patients with newly diagnosed myeloma, treated on Eastern Cooperative Oncology Protocol E9486 and Intergroup study 0141 (S9321) at the Mayo Clinic, were studied. Bone marrow microvessels were examined using immunohistochemical staining for von Willebrand factor. Determination of microvessel density and angiogenesis grading was done in a blinded manner. There was a strong correlation between microvessel density and the plasma cell labeling index, rho 0.42, P < 0.001. Angiogenesis grade was also significantly associated with the plasma cell labeling index. Fifteen % of patients with low-grade angiogenesis had a high labeling index (>1%). In contrast, 47% of patients with intermediate or high-grade angiogenesis had high labeling indices (P = 0.02). Overall survival was significantly different among those with high-, intermediate-, and low-grade angiogenesis, with median times of 2, 4, and 4.4 years, respectively (P = 0.02). Similarly, patients with microvessel density >50/x400 field had poorer survival compared with those with 50 or fewer microvessels/field, median survival 2.6 versus 5.1 years, respectively (P = 0.004). There was a strong association between angiogenesis grade and microvessel density (P < 0.001). We conclude that bone marrow angiogenesis is a predictor of poor survival in newly diagnosed myeloma. Angiogenesis is correlated with the plasma cell labeling index but not the bone marrow plasma cell percentage. A simple visual grading of angiogenesis is an efficient alternative to microvessel density estimation.