Analysis of microvessels in pancreatic cancer: by light microscopy,confocal laser scan microscopy,and electron microscopy

Background/Purpose

The microvessel density (MVD) of most malignant tumors is considered to be strongly related to metastasis and prognosis. Weidner’s “hot spot method” for determining MVD is in general use, but it is possible that cells other than endothelial cells will also be stained. In our previous study, no correlations were observed between MVD determined by the “hot spot method” and prognosis/metastasis. But, using the “lumen method,” we found a correlation with the number of vessel structures only. In the present study, we analyzed the staining of microvessels in pancreatic cancer, using light microscopy, confocal laser scan microscopy (CLSM), and transmission electron microscopy (TEM).

Methods

Microvessel staining of pancreatic cancer with CD34, factor VIII, and CD45 antibodies was examined in consecutive slices by light microscopy. For CLSM, freshly resected specimens were immunostained with factor VIII and fluorescein isothiocynate. For TEM, specimens were fixed with 2.5% glutaraldehyde, treated with 1% osmium tetroxide, and embedded in epoxy resin.

Results

Staining of vessels with CD34 and factor VIII antibodies appeared similar under light microscopy. However, CD34-stained consecutive slices were judged not to reveal vessel structures, and some cells stained with CD45 antibody were similar in appearance to CD34-stained cells. Under CLSM, irregular arrangements of neovascularization, consisting of many branches, were observed, but many positively stained cells not identified as vessels were also seen. Microvessels were distinctly identified under TEM, but the types of individual cells could not be determined.

Conclusions

An integrated, reproducible method for the measurement of MVD is vital. For pancreatic cancer, the “lumen method” is recommended.

     

Predictive value of microvascular density for response to anlotinib in advanced NSCLC

Nonsmall cell lung cancer (NSCLC) is the most common type of lung cancer. This study aimed to categorize the microvessels in advanced NSCLC and determine the relationship between intratumoral microvascular density (MVD) and the efficacy of anlotinib for NSCLC.The clinical data of 68 patients receiving anlotinib as third-line treatment or beyond for advanced NSCLC were retrospectively collected. Microvessels were stained for CD31 and CD34 by using immunohistochemical staining and were classified as undifferentiated (CD31+ CD34−) and differentiated vessels (CD31+ CD34+). The relationship between MVD and anlotinib efficacy and patient prognosis was analyzed.Patients were divided into the high or low MVD groups according to the median MVD of differentiated (9.4 vessels/field) and undifferentiated microvessels (6.5 vessels/field). There were significantly more patients with high undifferentiated-vessel MVD in the disease control group than in the disease progression group (72.7% vs 16.7%, P < .001). Patients with high undifferentiated-vessel MVD had significantly longer median progression-free survival than those with low undifferentiated-vessel MVD (7.1 vs 3.7 months, P < .001).Anlotinib as third- or beyond line therapy is safe and effective for advanced NSCLC. Patients with a higher density of undifferentiated microvessels have better response to anlotinib and longer progression-free survival.     

浸润性肺腺癌中Endoglin(CD105)的表达和血管新生状态研究

目的:对浸润性肺腺癌进行CD105的表达和血管新生状态研究,为在浸润性肺腺癌中,针对CD105的抗血管新生治疗的可能提供病理形态依据。方法:对46例浸润性肺腺癌标本进行CD31和CD105的免疫组化染色,测定肿瘤内区域及肿瘤旁形态正常肺泡组织的微脉管密度(MVD)。结果:在肿瘤旁形态正常肺泡组织中,平均MVD-CD31是106.7±41.0,在肿瘤内区域是54.5±22.6。在肿瘤旁形态正常肺泡组织中平均MVD-CD105是0.5±0.4,在肿瘤内区域是43.1±19.8。在肿瘤旁形态正常肺泡组织中MVD-CD105与MVD-CD31的比值是0.004±0.003,而在肿瘤内区域是0.781±0.104。两者之间比较差异有统计学意义(P<0.000 1)。结论:在浸润性肺腺癌肿瘤区域内血管特异性表达CD105。此发现可能会对未来以CD105为靶点的抗血管新生治疗,在浸润性肺腺癌中的应用,提供病理形态学依据。     

The antiangiogenic effect of thalidomide on occult liver metastases: An in vivo study in mice

Aim: To investigate the morphological changes of intratumoral microvessels after administration of thalidomide in occult hepatic metastases. Methods: Twenty mice with hepatic metastases created by injection of colon‐26 tumor cells into the spleen were enrolled. Ten mice were treated with thalidomide (200 mg/kg) by intraperitoneal injection daily from the first day after inoculation of tumor cells, and the other 10 with saline only. Fifteen days after tumor cell inoculation, the intratumoral microvessels of hepatic metastases in both groups were studied by intravital microscopy and immunohistochemistry. Results: For the control group, although the intratumoral microvessel density (MVD) and CD34 positive microvessel density (MVD‐CD34) of larger metastases (> 400 µm in diameter) were more than those of small metastases respectively (P < 0.01), the intratumoral branch density (BD) was similar to that of small metastases (P > 0.05). For the thalidomide treated group, despite the fact that MVD‐CD34 of larger metastases was more than that of small metastases (P < 0.01), the MVD and BD were similar to those of small metastases respectively (P > 0.05). The MVD, BD and MVD‐CD34 of small metastases of both groups were similar (P > 0.05); however, those of large metastases in the thalidomide treated group were significantly lower than those in the control group (P < 0.01). Conclusions: Thalidomide exerts an antiangiogenic effect on occult hepatic metastases with angiogenesis only, and the different vascular components in the tumor vasculature demonstrate various responses to antiangiogenic therapy.     

Three-dimensional reconstruction of tumor microvasculature: simultaneous visualization of multiple components in paraffin-embedded tissue

Three-dimensional (3D) visualization of microscopic structures may provide useful information about the exact 3D configuration, and offers a useful tool to examine the spatial relationship between different components in tissues. A promising field for 3D investigation is the microvascular architecture in normal and pathological tissue, especially because pathological angiogenesis plays a key role in tumor growth and metastasis formation. This paper describes an improved method for 3D reconstruction of microvessels and other microscopic structures in transmitted light microscopy. Serial tissue sections were stained for the endothelial marker CD34 to highlight microvessels and corresponding images were selected and aligned. Alignment of stored images was further improved by automated non-rigid image registration, and automated segmentation of microvessels was performed. Using this technique, 3D reconstructions were produced of the vasculature of the normal brain. Also, to illustrate the complexity of tumor vasculature, 3D reconstructions of two brain tumors were performed: a hemangioblastoma and a glioblastoma multiforme. The possibility of multiple component visualization was shown in a 3D reconstruction of endothelium and pericytes of normal cerebellar cortex and a hemangioblastoma using alternate staining for CD34 and alpha-smooth muscle actin in serial sections, and of a GBM using immunohistochemical double staining. In conclusion, the described 3D reconstruction procedure provides a promising tool for simultaneous visualization of microscopic structures.     

Microvessel organization and structure in experimental brain tumors: microvessel populations with distinctive structural and functional properties.

We studied microvessel organization in five brain tumor models (ENU, MSV, RG-2, S635cl15, and D-54MG) and normal brain, including microvessel diameter (LMVD), intermicrovessel distance (IMVD), microvessel density (MVD), surface area (S(v)), and orientation. LMVD and IMVD were larger and MVD was lower in tumors than normal brain. S(v) in tumors overlapped normal brain values and orientation was random in both tumors and brain. ENU and RG-2 tumors and brain were studied by electron microscopy. Tumor microvessel wall was thicker than that of brain. ENU and normal brain microvessels were continuous and nonfenestrated. RG-2 microvessels contained fenestrations and endothelial gaps; the latter had a maximum major axis of 3.0 microm. Based on anatomic measurements, the pore area of RG-2 tumors was estimated at 7.4 x 10(-6) cm(2) g(-1) from fenestrations and 3.5 x 10(-5) cm(2) g(-1) from endothelial gaps. Increased permeability of RG-2 microvessels to macromolecules is most likely attributable to endothelial gaps. Three microvessel populations may occur in brain tumors: (1) continuous nonfenestrated, (2) continuous fenestrated, and (3) discontinuous (with or without fenestrations). The first group may be unique to brain tumors; the latter two are similar to microvessels found in systemic tumors. Since structure-function properties of brain tumor microvessels will affect drug delivery, studies of microvessel function should be incorporated into clinical trials of brain tumor therapy, especially those using macromolecules.     

Increased angiogenesis in bone marrow of children with acute lymphoblastic leukaemia has no prognostic significance

The importance of angiogenesis for the growth and viability of solid tumours has been established. Similarly, prognostic information may be gained from the extent of angiogenesis in these tumours. Haematopoietic malignancies should have equal requirements for angiogenesis and important prognostic information may be derived from quantification of bone marrow angiogenic activity. We retrospectively investigated 82 bone marrow trephine biopsies from 41 children with acute lymphoblastic leukaemia (ALL) at diagnosis and following treatment. Nine normal bone marrow trephines from age-matched children were also analysed as controls. The microvessels were stained immunohistochemically with anti-Factor VIII-related antigen (antivWF) and antithrombomodulin (anti-THR). Angiogenesis was quantified manually by two independent observers and was highly reproducible (Pearson's r = 0.91). Staining with anti-vWF and anti-THR was highly specific for microvessels and thetwo stains closely correlated (r = 0.68). Microvessel densities (MVD) at presentation were significantly increased in the majority of patients in comparison with controls (P < 0.0001) and MVD dropped towards normal in remission (P < 0.0001). Of interest, the difference in total vessel counts between leukaemic and normal/remission marrows was contributed solely by small microvessels. There was no significant difference in MVD at presentation or remission from children in poor prognostic groups or those who subsequently relapsed. Similarly, we could not find an association with age, sex, cytogenetic abnormality or disease phenotype.     

Bone marrow-derived cells do not engraft into skeletal muscle microvasculature but promote angiogenesis after acute injury

The skeletal muscle is supported by a vast network of microvessels with the capacity to regenerate in response to injury. However, the dynamics of microvascular repair and the origin of reconstituted endothelial cells in the skeletal muscle are poorly understood. A growing body of literature exists to indicate bone marrow (BM)-derived cells engraft into regenerating vascular endothelium and muscle macrovasculature. Therefore, we investigated the extent of BM contribution to skeletal muscle microvasculature after acute injury. Because reporters and markers commonly used to trace donor BM cells are not endothelial specific but are also expressed by leukocytes, we generated novel BM chimeras utilizing Tie2-green fluorescent protein BM cells transplanted into CD31 and Caveolin-1 knockout recipients. In turn, we surveyed BM vascular contribution, not just by the presence of green fluorescent protein, but also CD31 and Caveolin-1, respectively. After stable BM reconstitution, chimera limb muscles were cardiotoxin (CTX) injured and examined 21 days post-injury for the presence of green fluorescent protein, CD31, and Caveolin-1. Acute muscle injury by CTX is characterized by initial microvasculature death followed by rapid endothelial regeneration within 14 days post-damage. Histological analysis of injured and uninjured contralateral limb muscles revealed a complete absence of BM engraftment in the muscle vasculature of wild-type and CD31/Caveolin-1 knockout chimeras. In contrast, F4/80(+) cells isolated from CTX-injured muscle, expressed endothelial-related markers and promoted angiogenesis in?vitro. Therefore, despite the absence of BM engraftment to regenerated skeletal muscle microvasculature, macrophages recruited after injury promote angiogenesis and, in turn, vascular regeneration.     

Three-dimensional reconstruction of tumor microvasculature: Simultaneous visualization of multiple components in paraffin-embedded tissue

Three-dimensional (3D) visualization of microscopic structures may provide useful information about the exact 3D configuration, and offers a useful tool to examine the spatial relationship between different components in tissues. A promising field for 3D investigation is the microvascular architecture in normal and pathological tissue, especially because pathological angiogenesis plays a key role in tumor growth and metastasis formation. This paper describes an improved method for 3D reconstruction of microvessels and other microscopic structures in transmitted light microscopy. Serial tissue sections were stained for the endothelial marker CD34 to highlight microvessels and corresponding images were selected and aligned. Alignment of stored images was further improved by automated non-rigid image registration, and automated segmentation of microvessels was performed. Using this technique, 3D reconstructions were produced of the vasculature of the normal brain. Also, to illustrate the complexity of tumor vasculature, 3D reconstructions of two brain tumors were performed: a hemangioblastoma and a glioblastoma multiforme. The possibility of multiple component visualization was shown in a 3D reconstruction of endothelium and pericytes of normal cerebellar cortex and a hemangioblastoma using alternate staining for CD34 and α-smooth muscle actin in serial sections, and of a GBM using immunohistochemical double staining. In conclusion, the described 3D reconstruction procedure provides a promising tool for simultaneous visualization of microscopic structures.     

Computerized morphometric analysis of microvasculature in non-small cell lung carcinoma

Interactions between tumor cells and microvasculature are particularly critical. This computerized morphometric study was designed to analyze the distance between cancer cells and blood vessels and microvasculature organization in non-small cell lung carcinoma (NSCLC) comparing squamous cell carcinoma (SCC) and adenocarcinoma (ADC). Seventy nine nests of tumor cells, located less than or more than 3 mm from the invading edge, with a similar surface area, and their surrounding stroma were analyzed. After immunolabeling with an antihuman CD34 monoclonal antibody, computerized morphometric analyses of microvascular density (MVD), distribution of microvessels within stroma, and fractions of carcinomatous cells over various distances from microvessels were performed. This analysis showed a significantly higher MVD score in ADC than in SCC, particularly close to the invading edge (382+/-57 in ADC <3 mm; 242+/-28 in SCC <3 mm, p=0.015). Moreover, a significantly higher proportion of cancer cells was situated more than 75 microm from microvessels in SCC than in ADC, regardless of their site in relation to the invading edge (for example, 25+/-5% in ADC <3 mm; 52+/-3% in SCC <3 mm, p=0.001).     

微血管密度与肝癌脉管侵袭关系的研究

探讨肿瘤新生微血管密度 (microvesseldensity,MVD)与原发性肝细胞癌 (hepatocellularcarcinoma ,HCC)脉管侵袭和转移的关系。采用免疫组化法 (streptavidinperoxidase ,S -P链霉素抗生物素蛋白 -过氧化酶 )对手术切除的 5 8例原发性肝细胞癌和 5 8例癌旁组织的石蜡包埋组织标本中的MVD进行了检测。在 4 0 0倍视野下选择 5个最密集区 ,记算MVD数量 ,取其均数。 (1)MVD在HCC组织中比癌旁组织明显增高 (P <0 0 1) ;(2 )HCC中有转移者及包膜不完整者 ,MVD明显高于无转移者及包膜完整者 ,(P <0 0 1) ;(3)HCC中脉管侵袭阳性组 ,MVD明显高于脉管侵袭阴性组 (P <0 0 1)。原发性肝细胞癌组织中的MVD与肿瘤的脉管侵袭和转移行为密切相关 ,可作为判定HCC转移及预后的指标     

Cardiovascular disease in patients with inflammatory rheumatic disease is associated with up‐regulation of markers of inflammation in cardiac microvessels and cardiomyocytes

Objective

Various inflammatory rheumatic diseases (IRDs) are associated with increased mortality due to cardiovascular disease. The aim of this study was to investigate heart biopsy specimens obtained from patients undergoing coronary artery bypass grafting and compare markers of inflammation and endothelial cell activation in the cardiac and skeletal muscle of patients with and those without IRD.

Methods

Paired biopsy specimens of cardiac and skeletal muscle were obtained from 22 consecutive patients with IRD and 8 patients without IRD, all of whom were undergoing coronary artery bypass grafting. The biopsy specimens were evaluated in a blinded manner by conventional microscopy and digital image analysis for cell markers (CD3, CD4, CD8, CD68, CD163, and CD31), HLA (HLA–ABC, HLA–DR, and HLA–DQ), adhesion molecules (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1), and proinflammatory cytokines (interleukin‐1α, interleukin‐1β, and tumor necrosis factor).

Results

Patients with IRD had significantly higher expression of adhesion molecules, proinflammatory cytokines, and all classes of HLA on cardiomyocytes and endothelial cells but no increase on mononuclear cells in the myocardium compared with patients without IRD. Furthermore, cardiac muscle from patients with IRD displayed significantly higher local expression of inflammation and activation of cardiac microvessels compared with skeletal muscle from the same patients.

Conclusion

Patients with cardiovascular disease had increased expression of adhesion molecules, HLA, and proinflammatory cytokines in heart tissue, indicating local inflammation involving microvessels and cardiomyocytes that could play a role in the pathogenesis of cardiovascular disease. The more pronounced changes in patients with IRD compared with patients without IRD might contribute to the increased risk of cardiovascular disease and premature death in patients with IRD.

     

非小细胞肺癌中基质金属蛋白酶10与CD105的表达及其意义

目的探讨基质金属蛋白酶10（MMP10）、CD105在非小细胞肺癌（NSCLC）组织中的表达及其临床意义。方法用免疫组织化学SP法检测60例NSCLC组织和20例正常肺组织中MMP10、CD105的表达水平,并分析MMP10、CD105过表达与NSCLC临床病理特征的关系。结果NSCLC中MMP10阳性率和CD105标志的肿瘤微血管密度（MVD）的表达强度明显高于正常组织中的表达（P均〈0.05）;二者的表达强度与分化程度、TNM分期、有无淋巴结转移有关（P均〈0.05）,与组织类型、年龄、性别、吸烟史无关;MMP10过表达组中CD105标志的肿瘤MVD显著高于非过表达组。结论MMP10、CD105参与了NSCLC发生发展过程,并可能与肿瘤血管生长有关。     

微血管密度与CD105、CD31在胃癌中的表达及意义

目的探讨胃癌组织中微血管密度（microvessel density,MVD）与CD105、CD31的表达及生物学行为的关系。方法取61例术前未作放、化疗及免疫治疗胃癌病人的外科手术切除标本,采用免疫组织化学技术S-P法检测CD105、CD31的表达,并定量计数胃癌组织微血管。结果胃癌组织中CD105及CD31标记的MVD在与淋巴结转移、肿瘤浸润深度均有显著性差异（P〈0．05）;Kaplan．Meier法分析显示微血管计数CD105〈14个,CD31〈34个（200×）的胃癌病人预后较好,而微血管计数CD105≥14个,CD31≥34个（200×）预后较差。结论胃癌MVD与其生物学行为有关,提示肿瘤血管生成分析和微血管密度计数是评价胃癌预后的一项重要参考指标。     

Immunohistochemical expression of vascular endothelial growth factor (VEGF) does not correlate with microvessel density in renal cell carcinoma

The aim of present study was to investigate the relationship between the immunohistochemical expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) assessed by CD31 and endoglin (CD105) in renal cell carcinoma (RCC). Specimens from 45 cases of RCC. were formalin-fixed, paraffin embedded, and sections were stained with H&E. Additional sections from each case were stained for VEGF, CD31, CD105, and alpha smooth muscle cell actin (SMA). VEGF immunohistochemical expression was estimated as negative (0), weak positive (+1), moderate positive (+2), and intense positive (+3). Microvessel density (MVD) was estimated on 5 hot spots (x400) from each case, and the arithmetic media was the final result. MVD was separately calculated on slides stained with CD31 and CD105. The rate between mature and immature blood vessels was calculated on slides stained with CD31/CD105/SMA. Statistic analysis was performed with SPSS10.0. The immunoreaction for VEGF was positive in epithelial cells of the renal tubules, and occasionally, in endothelial cells. In RCC, tumor cells were positive in 34 from 45 cases (75.5%). 11 cases were negative, 14 were slightly positive (+1), 13 moderate (+2), and 7 intense (+3). No relationship was found between the expression of VEGF and pathological form and nuclear grade, excepting for the chromophilic variant (3 cases, all positive). CD31 was positive in all cases, and CD105 in 39 cases. The mean values of MVD on slides stained for CD31 and CD105 were: 31.68 (range 9.8-60.2)/20.66 (range 4.2-52.8). The rate CD31/SMA positive blood vessels was 1/0.62. VEGF was expressed in 75.5% of 45 cases with RCC, and the mean value of MVD CD31/CD105 was 31.68/20.66. The immunohistochemical expression of VEGF does not correlate with MVD performed on slides stained for both CD31 and endoglin. The majority of blood vessels in the tumor area are of mature type, with perivascular cells positive for SMA.     

Hypertension-independent microvascular rarefaction in the obese Zucker rat model of the metabolic syndrome

OBJECTIVE: To test the hypothesis that reduced skeletal muscle microvessel density (MVD) in obese Zucker rats (OZR) is independent of chronic elevations in mean arterial pressure (MAP). METHODS: Microvessels in cross sections of gastrocnemius muscle from lean Zucker rats (LZR) and OZR were labeled with Griffonia simplicifolia I lectin, visualized with fluorescence microscopy and vessel number within sections was determined using imaging software. Rats were used at different ages to assess correlations between the temporal development of hypertension and microvascular rarefaction. Additionally, rats were chronically treated with captopril or hydralazine as antihypertensive therapies to examine the development of microvascular rarefaction in the absence of elevated blood pressure. RESULTS: MVD in muscle of OZR was reduced by approximately 17% versus LZR by 10-11 weeks of age, prior to any elevation in MAP. By 15-17 weeks, OZR exhibited a approximately 23% reduction in MVD and a approximately 25 mmHg increase in MAP. Treatment with hydralazine prevented elevated MAP in OZR, although this was not associated with an improved MVD. Captopril treatment also prevented elevated MAP in OZR, although a partial recovery of MVD toward normal levels was observed. This observation was associated with an improved insulin resistance. CONCLUSIONS: These results suggest that microvessel rarefaction in skeletal muscle of OZR manifesting the metabolic syndrome does not depend on an elevated mean arterial pressure and that other factors associated with the metabolic syndrome, possibly insulin resistance, may underlie the progressive reduction in MVD in these animals.     

Angiogenic markers endoglin and vascular endothelial growth factor in gastroenteropancreatic neuroendocrine tumors

AIM:To investigate the expression and potential prognostic role of vascular endothelial growth factor(VEGF) and endoglin in gastroenteropancreatic neuroendocrine tumors(GEP-NETs) . METHODS:Microvessel density(MVD) in GEP-NETs was evaluated using endoglin and CD31 immunohistochemistry.In addition,tissue levels of endoglin and VEGF were determined in homogenates by ELISA. RESULTS:Endoglin was highly expressed on tumor endothelial cells.CD31 MVD in GEP-NETs was significantly higher compared to endoglin MVD(P<0...     

门静脉高压大鼠胃黏膜及微血管增生程度的初步研究

目的研究门静脉高压性胃病胃黏膜及微血管增生情况.方法采用改良四氯化碳吸入法建立大鼠肝硬化门静脉高压的胃黏膜病变模型,通过光学显微镜研究其胃黏膜及微血管病理变化并利用免疫组织化学染色研究增殖细胞核抗原(PCNA)和胃黏膜微血管密度(MVD)的分布.结果光镜下门静脉高压时大鼠胃黏膜呈现全胃黏膜和微动静脉充血,毛细血管扩张、膨胀;门静脉高压症大鼠胃黏膜PCNA表达较正常明显增高(P＜0.01),PCNA表达集中在黏膜固有层;门静脉高压症大鼠胃黏膜微血管数目较正常明显增多(P＜0.01).结论肝硬化门静脉高压症大鼠胃黏膜细胞增殖明显(可以从PCNA的表达及分布规律中体现出来),胃黏膜微血管数目亦显著增多.     

CD133在肺癌中的研究与进展

肺癌是世界范围内死亡率最高的恶性肿瘤之一,也是我国常见的恶性肿瘤之一,恶性程度高,发展迅速,治疗困难,总体疗效不理想。肿瘤干细胞是肿瘤组织中一小部分具有自我更新、无限增殖和多向分化能力的肿瘤细胞,它在肿瘤组织中所占比例虽然很少,却与肿瘤起源、发展与转移关系密切,因此肿瘤干细胞被看作是一个根除癌症的潜在目标。CD133是...     

Bone marrow angiogenesis and its correlation with other disease characteristics in multiple myeloma in stage I versus stage II-III

PURPOSE: We studied bone marrow angiogenesis in different stages of multiple myeloma according to the Durie and Salmon classification and its correlations with other disease characteristics. METHODS: Sixty-five immunohistochemical CD34-stained, paraffin-embedded bone marrow biopsies of multiple myeloma patients and 12 controls were studied. The mean number of microvessels per area in each sample was determined as the microvessel density (MVD). In addition, plasma cell infiltration of the bone marrow, serum beta2-microglobulin, immunoglobulin levels, C-reactive protein, and serum calcium concentration were measured in 22 patients with stage I multiple myeloma and in 43 patients in stage II-III. RESULTS: In myeloma patients, the bone marrow MVD was significantly higher than in controls (P<0.001). In 43 patients with stage II-III multiple myeloma, MVD was significantly higher than in 22 patients with stage I (median MVD 46 and 21 vessels/mm(2), respectively, P=0.005). Additionally, in stage II-III the bone marrow MVD correlated positively with the bone marrow plasma cell infiltration (r=0.55, P<0.001) and the serum beta2-microglobulin level (r=0.53, P<0.001), while in stage I patients no correlation could be found. CONCLUSIONS: Angiogenesis is significantly increased in stage II-III myeloma in comparison to stage I. In stages II-III, bone marrow angiogenesis is correlated with plasma cell infiltration and serum beta2-microglobulin levels.