Bone marrow angiogenesis in multiple myeloma and its correlation with clinicopathological factors

Increased angiogenesis has been found to be an adverse prognostic factor in solid tumors but evidences show that angiogenesis also plays an important role in hematological malignancies including multiple myeloma (MM). In this report we studied the various angiogenesis parameters like microvessel density (MVD) and total vascular area (TVA), on bone marrow biopsies in 50 newly diagnosed cases of MM. The aim was to study bone marrow angiogenesis in MM using light microscopy (MVD-A) and computerized image analyzer (MVD-B and TVA) and correlate it with clinical features, laboratory findings, histological features, and response to treatment on follow-up. Bone marrow biopsies of test cases (n = 50) were immunohistochemically stained with CD34 for visualization of microvessels. MVD-A (range 8–80; mean 50.4; SD 17.5), MVD-B (5.2–33.2; mean 16.3; SD 5.1), and TVA in percentage (range 0.42–7.20; mean 2.8; SD 1.5) were measured. Ten age- and sex-matched controls were studied and their parameters were taken as grade I. There was a significant correlation between these angiogenesis parameters (MVD-A vs MVD-B, Pearson’s correlation coefficient (pcc) = 0.724; MVD-A vs TVA, pcc = 0.370; MVD-B vs TVA, pcc = 0.406). The angiogenesis was significantly higher in cases as compared to controls. Patients with residual disease had a higher MVD as compared to the complete responders. High tumor burden and diffuse pattern of infiltration were also associated with grade III MVD and TVA. Hence, it can be concluded that angiogenesis correlates with other histological features associated with prognosis and is also a good predictor for complete response in patients with multiple myeloma.     

Bone marrow angiogenesis and progression in multiple myeloma

Tumour growth is angiogenesis-dependent. We found a high correlation between the extent of bone marrow angiogenesis, evaluated as microvessel area, and the proliferating (S-phase) fraction of marrow plasma cells, evaluated as labelling index (LI), in patients with multiple myeloma (MM) and in those with monoclonal gammopathies of undetermined significance (MGUS). Angiogenesis itself was significantly associated with active as opposed to non-active MM and MGUS. The highest microvessel area accompanied rapidly progressive MM with the highest LI. When a cut-off value of 2% or greater of the microvessel area was used, most patients with active MM were classified correctly. The risk of active disease in patients with MM increased in parallel with the microvessel area. A causal relationship between plasma cell growth, activity phase in MM and marrow angiogenesis is suggested. Since angiogenesis proceeds in step with the enlargement of plasma cell tumours and the activity phase in MM, its measurement could be a useful prognostic marker in patients with plasma cell proliferative disorders.     

Bone marrow angiogenesis and circulating plasma cells in multiple myeloma

Bone marrow (BM) angiogenesis is increased in multiple myeloma (MM) and has prognostic significance. The presence of circulating plasma cells (PCs) in MM is associated with a poorer prognosis. We examined BM biopsies obtained at diagnosis of MM for angiogenesis, and correlated the microvessel density (MVD) with the presence of circulating PCs. There was a positive correlation between the absolute number of circulating PCs and the mean MVD. This relationship was independent of the disease activity and of the PC burden in the marrow. The increased angiogenesis may promote plasma cell proliferation and enable PC migration into the circulation.     

Bone marrow angiogenesis in multiple myeloma: effect of therapy

Recent studies have demonstrated that angiogenesis has a role in haematological malignancies, including multiple myeloma. Multiple myeloma is characterized by inevitable relapse after standard or high-dose chemotherapy. To study the effect of chemotherapy on bone marrow angiogenesis in patients with multiple myeloma, we used two methods to evaluate bone marrow angiogenesis in patients with newly diagnosed multiple myeloma, comparing these findings with those from bone marrow obtained after standard chemotherapy. Before therapy, an increased degree of bone marrow angiogenesis and a high bone marrow plasma cell labelling index (PCLI) were predictive of poorer survival. As estimated by microvessel density (MVD), the median survivals for patients with low-grade, intermediate-grade and high-grade angiogenesis were 77, 30 and 14 months respectively. After therapy, the MVD did not change significantly. However, when patients with at least a partial response were considered separately, they showed a decrease in MVD. Post-therapy PCLI was predictive of survival, but post-therapy MVD was not. There was good correlation between angiogenesis estimated by visual grading and that determined by MVD assessment. We conclude that the degree of bone marrow angiogenesis is a prognostic marker in patients with multiple myeloma and does not decrease significantly after therapy.     

Bone marrow transplantation in multiple myeloma

We report 3 cases of allogeneic bone marrow transplantation in multiple myeloma that we have recently performed. Following conditioning treatment with i.v. cyclophosphamide (60 mg/kg/d, for 2 d), oral melphalan (1.0 mg/kg/d, for 5 d), i.v. BCNU (5.5 mg/kg, in a single dose) and total body irradiation (10 Gy in a single fraction) we observed in all 3 cases the disappearance both of serum M component and of monoclonal bone marrow plasma cells. 1 patient died of acute GVH disease, grade IV, at 2 months, while the other 2 patients are in good health and in unmaintained complete remission at 4 and 20 months, respectively. The usefulness of allogeneic bone marrow transplantation in the management of multiple myeloma is emphasized.     

Bone marrow angiogenesis and plasma cell angiogenic and invasive potential in patients with active multiple myeloma

Factor VIII-related antigen-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 5- to 6-fold larger area was found in patients with active MM compared to the other two groups. The conditioned medium (CM) of their bone marrow plasma cells stimulated endothelial cell proliferation and chemotaxis, monocyte chemotaxis and angiogenesis in vivo [chick embryo chorioallantoic membrane (CAM) system] more strongly and frequently than the CM of patients with nonactive MM and MGUS. An 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 54-68% the biological activity exerted by the CM in vitro and in the CAM. In situ hybridization of bone marrow plasma cells and gelatin 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 suggest that patients with active MM represent the vascular phase of plasma cell tumors that is triggered by bone marrow plasma cells, at least partly, through FGF-2 and MMP-2. Both angiogenesis and MMP-2 secretion can account for intramedullary and extramedullary spreading of plasma cells during the active MM.     

Syndecan-1 and angiogenic cytokines in multiple myeloma: correlation with bone marrow angiogenesis and survival

Angiogenesis is a complex process involved in the proliferation and metastasis of malignant tumours, and partly triggered by the secretion of various angiogenic factors by tumour cells or cells in the stromal environment. We investigated the correlation between bone marrow angiogenesis, estimated as microvessel density (MVD), and interleukin-6 (IL-6), basic fibroblastic growth factor (bFGF), hepatocyte growth factor (HGF) and syndecan-1 in 67 patients with newly diagnosed multiple myeloma, and evaluated the prognostic value of these parameters. Circulating levels of IL-6, bFGF, HGF and syndecan-1 were significantly higher in patients than in controls. Moreover, in patients, bone marrow levels of bFGF, HGF and syndecan-1 were higher than peripheral blood levels. Positive correlations were found between MVD and syndecan-1 blood levels (r = 0.33, P = 0.017), syndecan-1 bone marrow levels (r = 0.49, P = 0.046) and HGF blood levels (r = 0.36, P = 0.008) respectively. High MVD and high blood levels of IL-6, HGF and syndecan-1 were predictive of a shorter survival. In a multivariate survival analysis MVD and blood levels of IL-6 retained independent prognostic significance, while in a survival analysis without MVD the peripheral blood levels of HGF and syndecan-1 were strong independent prognostic factors.     

Circulating plasma cells in multiple myeloma: characterization and correlation with disease stage

The aim of this study was to develop a flow cytometric test to quantitate low levels of circulating myeloma plasma cells, and to determine the relationship of these cells with disease stage. Cells were characterized using five-parameter flow cytometric analysis with a panel of antibodies, and results were evaluated by comparison with fluorescent consensus-primer IgH-PCR.
Bone marrow myeloma plasma cells, defined by high CD38 and Syndecan-1 expression, did not express CD10, 23, 30, 34 or 45RO, and demonstrated weak expression of CD37 and CD45. 65% of patients had CD19⁻56⁺ plasma cells, 30% CD19⁻56^low, and 5% CD19⁺56⁺, and these two antigens discriminated myeloma from normal plasma cells, which were all CD19⁺56^low.
Peripheral blood myeloma plasma cells had the same composite phenotype, but expressed significantly lower levels of CD56 and Syndecan-1, and were detected in 75% (38/51) of patients at presentation, 92% (11/12) of patients in relapse, and 40% (4/10) of stem cell harvests. Circulating plasma cells were not detectable in patients in CR ( n =9) or normals ( n =10), at a sensitivity of up to 1 in 10 000 cells. There was good correlation between the flow cytometric test and IgH-PCR results: myeloma plasma cells were detectable by flow cytometry in all PCR positive samples, and samples with no detectable myeloma plasma cells were PCR negative. Absolute numbers decreased in patients responding to treatment, remained elevated in patients with refractory disease, and increased in patients undergoing relapse. We conclude that flow cytometry can provide an effective aternative to IgH-PCR that will allow quantitative assessment of low levels of residual disease.     

Long-term survival and prognostic factors in stage II-III multiple myeloma treated with conventional chemotherapy]

In this retrospective study, survival and prognostic factors were analysed in 65 patients with stage II-III multiple myeloma with osteolytic lesions. Multiple myeloma was diagnosed from 1976 to 1984, and patients were treated with conventional chemotherapy. The response rate to initial chemotherapy was 46%. The median survival time was 31 months. The 10-year survival rate was 10%. Four variables were individually prognostic: response to initial chemotherapy, bone marrow plasma cell percentage, the Durie and Salmon staging system, a biological staging system derived from Durie and Salmon's biological criteria regardless of bone lesions. In the multivariate analysis, only two prognostic variables were retained, namely the response to chemotherapy and the biological staging system. No prognostic value was observed for the extent of osteolytic lesions. This study suggests that, in conventionally treated multiple myeloma, long-term survival has improved compared with the previous decade. It also indicates that the extent of osteolytic lesions has little value for the definition of high-risk myeloma.     

Prognostic value of bone marrow plasma cell infiltration in stage I multiple myeloma

S ummary. We analysed for prognosis and response to chemotherapy a series of 48 consecutive stage I myeloma patients who were treated with melphalan and prednisone soon after diagnosis. It was found that the extent of bone marrow plasma cell infiltration had prognostic value, the survival of the patients with more than 50% plasma cells being significantly shorter ( P <0·005) than that of the patients with less than 50% plasma cells. In the latter group, the observed number of deaths was so small (two cases) as to preclude any further analysis. In contrast, in the former group, a significant relationship between the response to chemotherapy and patients' survival ( P <0·001) was demonstrated. We conclude that a prospective randomized trial of treatment versus no treatment is warranted in stage I patients who have a high risk of death (i.e. with a high bone marrow plasma cell infiltration) in order to establish whether chemotherapy prolongs the length of survival.     

Serum levels of interleukin-6 in multiple myeloma and other hematological disorders: correlation with disease activity and other prognostic parameters

Summary Interleukin-6 (IL-6) is a multifunctional cytokine involved in the regulation of the terminal differentiation pathway of B lymphocytes. Recent reports revealed its potential role in the in vitro and in vivo growth of human multiple myeloma cells. The mechanism, however, by which IL-6 triggers proliferation of malignant plasma cells remains controversial. Using the very sensitive 7TD1 bioassay we quantified endogenous circulating IL-6 levels in serum samples of 104 patients suffering from monoclonal gammopathies and other hematological disorders [47 with multiple myeloma (MM), 24 with monoclonal gammopathy of unknown significance (MGUS), 8 with myeloproliferative disease, and 25 suffering from lowgrade non-Hodgkin's lymphoma (NHL)]. Elevated serum levels of IL-6 (>5 pg/ml) were detected in 42% of the patients with MM, in 13% with MGUS, in 15% with low-grade B-NHL, and in 1 patient with T-NHL. In patients suffering from chronic myeloproliferative diseases, IL-6 levels were within the normal range. In patients with myeloma, IL-6 levels were significantly higher at advanced stages (II/III) or with progressive disease than in patients with MM stage I, MGUS, or at the plateau phase (P<0.01). In patients with monoclonal gammopathies including MGUS, serum IL-6 levels correlated with neopterin, tumor necrosis factor alpha and ₂-microglobulin. An inverse correlation was found with hemoglobin levels. From these results, we propose that in myeloma patients serum IL-6 levels may reflect disease activity and tumor cell mass. The correlation with serum neopterin, a macrophage product, also suggests its origin in an activated immune system.     

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.