VEGF-A Staining Research Articles

Placental vascularization in middle and late gestation in the pig.

The aims of this study were to determine the changes in the capillary area density in relation to fetal development, to determine immunoexpression of angiogenic factors and to compare their mRNA expression throughout pig gestation. Samples were collected from the maternal-chorioallantoic interface at days 40, 77, 85 and 114 of pregnancy for immunohistochemistry analysis and the measurement of mRNA expression of VEGFA, ANGPT1, ANGPT2, FGF2 and its receptors KDR, TEK, FGFR1, FGFR2respectively. Morphometric measurement of blood vessels was performed. We found a significant increase in capillary area density throughout gestation (P< 0.05). On the maternal side, at day 77, we observed a significant increase in the number of vessels from small vascular areas (P < 0.05) and the vascular area was significantly higher on day 85 (P < 0.05). On the fetal side, the number of vessels and the vascular area increased between days 40 and 77 (P < 0.05) and between days 77 and 114 (P < 0.05), respectively. Immunohistochemical findings revealed intense VEGFA staining and a trend for increased expression towards the end of gestation (P < 0.05). We also demonstrated a high VEGFA, FGF2, FGFR1, ANGPT1 and ANGPT2mRNA expression at day 77 (P < 0.05). In conclusion, our findings suggest that an active angiogenesis would be present even until late-middle gestation at day 77 of pregnancy with the predominance of angiogenic stimulation by VEGFA/KDR, FGF2/FGFR1 and a balance between ANGPT1 and ANGPT2/TEK.Lay summaryCritical moments occur at different stages of placental formation in pigs, where the expression of angiogenic factors, that is, molecules that stimulate the formation of blood vessels must be adequate to promote their development. This exchange is necessary to cover the increasing nutritional demands of fetuses in continuous development. Determining the changes in the area of capillary density in relation to fetal development and the expression of angiogenic factors throughout pregnancy in pigs could contribute to understanding the causes of fetal loss. Placental samples were obtained at gestational days 40, 77, 85 and 114 (n = 7, 10, 7 and 5, respectively). We found that the capillary area density increases accompanying fetal growth with advancing gestation and an increase in capillary area density in late-middle gestation, around day 77, is due to the expansion in the number of small blood vessels on the maternal side. The present findings suggest that an intense angiogenesis would be present even until late-middle gestation at day 77 of pregnancy, with the predominance of angiogenic stimulation by specific molecules that promote this process.

TAFRO syndrome as a cause of glomerular microangiopathy: a case report and literature review

BackgroundTAFRO syndrome is a systemic inflammatory disorder that manifests as thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (R), and organomegaly (O). Renal dysfunction is frequently complicated with TAFRO syndrome, however, it is challenging to perform kidney biopsy in patients with TAFRO syndrome in the presence of thrombocytopenia. Renal histology in TAFRO syndrome mainly shows membranoproliferative glomerulonephritis (MPGN)-like lesions or thrombotic microangiopathy (TMA)-like glomerulopathy. We review our case and previous reports of TAFRO syndrome with kidney biopsy findings and discuss the renal pathophysiology of TAFRO syndrome.Case presentationWe describe a previously healthy 48- year-old woman with TAFRO syndrome. Kidney biopsy performed before the treatment showed diffuse global endocapillary proliferative changes with endothelial cell swelling, double contours of partial capillary walls, and mesangiolysis, consistent with TMA-like glomerulopathy. Glucocorticoid therapy including steroid pulse was ineffective and she developed anasarca, renal dysfunction and oliguria. Hemodialysis was required. However, the anti-Interleukin (IL)-6 receptor antibody (tocilizumab) therapy was very effective. An increase in urinary volume was achieved about 2 weeks after the tocilizumab therapy and hemodialysis was discontinued. To investigate the renal pathophysiology of TAFRO syndrome, we performed immunohistological staining of vascular endothelial growth factor (VEGF)-A, CD34, and D2–40, in our case and a normal control kidney. Glomerular VEGF-A was especially positive in podocytes both, in the control and in the case, with no significant difference and there was a significant increase of VEGF-A staining area in the cortical peritubular capillaries in the case. Both glomerular and renal cortical CD34 expression were significantly decreased in our case. D2–40 expression in cortex was not significantly different.ConclusionsWe reviewed our case and other 10 previous reports about renal biopsy findings in TAFRO syndrome and found that glomerular microangiopathy was a common finding. IL-6-VEGF-axis-induced glomerular microangiopathy may play a crucial role in developing acute kidney injury in TAFRO syndrome and the anti-IL-6 receptor antibody therapy may be useful for TAFRO syndrome refractory to glucocorticoids. About the pathophysiology of VEGF in TAFRO syndrome, VEGF balance in the glomerulus and perhaps in the peritubular capillary system as well may be critical. Further investigation is needed.

Cytoplasmic E-Cadherin Expression Is Associated With Higher Tumour Level of VEGFA, Lower Response Rate to Irinotecan-based Treatment and Poorer Prognosis in Patients With Metastatic Colorectal Cancer.

The prognostic value of vascular endothelial growth factor-A (VEGFA) and epithelial cadherin (E-cadherin) expression in patients with metastatic colorectal cancer (mCRC) is controversial. In this prospective study, patients diagnosed with mCRC between August 1, 1998, and August 30, 2003, at the Turku University Hospital, Finland were included. Expression of E-cadherin (membranous and cytoplasmic pattern) and VEGFA in tumour samples was assessed by immunohistochemistry. Tumours were classified as E-cadherin expressers if they demonstrated moderate or strong cytoplasmic or membranous staining, while those positive for VEGFA expression showed a moderate or strong cytoplasmic staining. Of particular interest was the association between membranous or cytoplasmic expression of E-cadherin and VEGFA. The value of strong VEGF-A staining and membranous or cytoplasmic expression of E-cadherin as a predictor of disease outcome over a 6-year period was another point of interest in this study. Of the 67 patients with mCRC, 43 (64%) had tumours positive for cytoplasmic E-cadherin, while in 24 cases (36%), E-cadherin expression was membranous. Strong VEGFA staining was present in half of the cases (n=36, 54% of all 67 mCRC cases). VEGFA expression was significantly correlated with cytoplasmic E-cadherin expression in that 28/36 cases of VEGFA-positive tumours were also positive for cytoplasmic E-cadherin (p=0.012). In addition, among the patients with intense VEGFA expression (n=36), those who had positive cytoplasmic E-cadherin in their tumours had a lower response-rate to first-line therapy with irinotecan, fluorouracil and leucovorin regimen: 5 out of 36 (14%) were chemosensitive. This is in contrast to the patients with VEGFA-positive tumours and membranous E-cadherin (8/36, 22% chemosensitive (p=0.004). The former group also had more ominous prognosis (p<0.001). Reduced membranous expression of E-cadherin and increased cytoplasmic E-cadherin expression predict poor survival in mCRC.

Leucine-Rich α-2-Glycoprotein-1 (LRG-1) Expression in Retinoblastoma.

Retinoblastomas' growth rate is dependent on their ability to induce neovascularization. Leucine-rich α-2-glycoprotein-1 (LRG-1) was recently reported to be upregulated in human retinal disease with neovascular pathology. The purpose of the study was to determine LRG-1 expression in human retinoblastoma and to correlate it with clinical and histopathologic parameters and to assess how its expression correlates with vascular endothelial growth factor (VEGF) expression. LRG-1 expression was immunohistochemically evaluated in 34 retinoblastoma sections. Immunofluorescence for LRG-1/VEGF-A, LRG-1/TGF-β1/CD31, and LRG-1/Ki67 was performed. Quantitative RT-PCR analysis for the expression of LRG-1 was also done. LRG-1 was found to be extensively and robustly expressed in retinoblastoma tumors (88%) irrespective of the degree of invasiveness, differentiation, iris neovascularization, and anterior segment involvement. LRG-1 immunoreactivity was predominantly observed in the central tumor vasculature and in the surrounding rim of ischemia. The higher frequency of LRG-1 expression in the presence of optic nerve infiltration, vitreous seeding, and necrosis was not statistically significant. Colocalization was observed between LRG-1 and VEGF-A staining, and no difference in their counts was detected. Quantitative RT-PCR analysis showed that LRG-1 gene expression was significantly upregulated (4.8-fold increase, P = 0.01). LRG-1 was highly expressed in human retinoblastoma sections, thus providing new insights into the molecular mechanism of retinoblastoma pathogenesis, and suggests a possible new therapeutic target. LRG-1 is a novel oncogene-associated protein shown to be vital to the progression of human cancers. Inhibiting tumor vasculature is progressively evolving as a target in anticancer therapy.

The relationship of the angiogenesis regulators VEGF-A, VEGF-R1 and VEGF-R2 to p53 status and prognostic factors in epithelial ovarian carcinoma in FIGO-stages I-II.

The aim of this study was to evaluate prognostic effect of the angiogenesis regulators VEGF-R1, VEGF-R2 and VEGF-A for recurrent disease and disease-free survival (DFS), and their relation to the apoptosis regulator p53, in 131 patients with FIGO-stages I–II with epithelial ovarian cancer. For the detection of positivity of the markers the techniques of tissue microarrays and immunohistochemistry (IHC) were used. In tumors the frequency of positive staining for VEGF-R1 was 19%, for VEGF-R2 and VEGF-A, it was 77 and 70%, respectively. Positivity for p53 was detected in 25% of tumors. The total number of recurrences in the complete series was 34 out of 131 (26%) and 5-year disease-free survival (DFS) was 68%. Positive staining for VEGF-A (P=0.030), VEGF-R2 (P=0.011) and p53 (P=0.015) was found more frequently in type II tumors than in type I tumors. Patients with VEGF-R1 negative tumors had worse (P=0.021) DFS compared to patients with VEGF-R1 positive tumors. In two multivariate Cox analyzes with DFS as endpoint, FIGO-stage (HR=3.8), VEGF-R2 status (HR=0.4) and p53 status (HR=2.3), all were significant and independent prognostic factors. When the variables VEGF-R2 and p53 were replaced with the new variable VEGF-R2+p53−/other three combinations in one group, it was found that patients from that subgroup had 86% reduced risk of dying in disease (HR=0.24). Findings above, confirmed relationship between VEGF-R2 and VEGF-A and p53, respectively, with regard to recurrent disease and survival. Some findings from the present study are different from results from previous studies on the regulation of angiogenesis. Despite many trials with anti-angiogenic agents in the front line of ovarian cancer have shown to be positive for progression-free survival, no one has demonstrated an impact on overall survival. Therefore, one of the greatest challenges in ovarian cancer research, is to discover predictive and prognostic biomarkers.

PO73 OUTPATIENT CATUMAXOMAB THERAPY IN METASTATIC BREAST CANCER PATIENTS SUFFERING FROM MALIGNANT EFFUSIONS DUE TO PERITONEAL OR PLEURAL CARCINOMATOSIS: A SINGLE INSTITUTION EXPERIENCE

s / The Breast 24 S3 (2015) S21–S75 S47 cells. Loss, increase, or no change in ER staining in primary tumour and pleural effusion specimens was observed in 7, 0 and 21 cases (19 cases were positive, 2 cases were negative), respectively. In two of these 19 cases with ER positive, endocrine therapy was performed. In one of two patients, endocrine therapy achieved long stable disease. However, endocrine therapies were ineffective in all cases of ER loss in pleural effusion specimens. No discrepancy of HER2 expression from primary tumours and pleural effusion specimens were confirmed. Positive staining cell for VEGF-A was found to be present in 75% of pleural effusion specimens (15 of 20 specimens). Eight pleural effusion specimens were not available to VEGF-A staining because of a few carcinoma cells. In 2 of these 15 cases with VEGF-A positive, bevacizumab antiangiogenic agents were administered. Therapeutic effects were confirmed in both patients. However, these agents were administered in 2 of 5 cases with VEGF-A negative and therapeutic effects were confirmed in one patient. Conclusions: The results of this study emphasize the reliability of immunohistochemistry in pleural effusion specimens. Therapeutic effect prediction based on biomarkers in the pleural effusion specimens of breast cancer patients may be promising in loss cases of ER staining.

Exercise preconditioning improves traumatic brain injury outcomes

PurposeTo determine whether 6 weeks of exercise performed prior to traumatic brain injury (TBI) could improve post-TBI behavioral outcomes in mice, and if exercise increases neuroprotective molecules (vascular endothelial growth factor-A [VEGF-A], erythropoietin [EPO], and heme oxygenase-1 [HO-1]) in brain regions responsible for movement (sensorimotor cortex) and memory (hippocampus). Methods120 mice were randomly assigned to one of four groups: (1) no exercise+no TBI (NOEX-NOTBI [n=30]), (2) no exercise+TBI (NOEX-TBI [n=30]), (3) exercise+no TBI (EX-NOTBI [n=30]), and (4) exercise+TBI (EX-TBI [n=30]). The gridwalk task and radial arm water maze were used to evaluate sensorimotor and cognitive function, respectively. Quantitative real time polymerase chain reaction and immunostaining were performed to investigate VEGF-A, EPO, and HO-1 mRNA and protein expression in the right cerebral cortex and ipsilateral hippocampus. ResultsEX-TBI mice displayed reduced post-TBI sensorimotor and cognitive deficits when compared to NOEX-TBI mice. EX-NOTBI and EX-TBI mice showed elevated VEGF-A and EPO mRNA in the cortex and hippocampus, and increased VEGF-A and EPO staining of sensorimotor cortex neurons 1 day post-TBI and/or post-exercise. EX-TBI mice also exhibited increased VEGF-A staining of hippocampal neurons 1 day post-TBI/post-exercise. NOEX-TBI mice demonstrated increased HO-1 mRNA in the cortex (3 days post-TBI) and hippocampus (3 and 7 days post-TBI), but HO-1 was not increased in mice that exercised. ConclusionsImproved TBI outcomes following exercise preconditioning are associated with increased expression of specific neuroprotective genes and proteins (VEGF-A and EPO, but not HO-1) in the brain.

1687 - VEGF and VEGF Receptors in Thymic Epithelial Tumors (Tet): Pathological Features and Clinical Implications

ABSTRACT Background Thymic Epithelial Tumors (TET) are very rare cancers. They derives from Thymic gland and are associated with different clinical syndromes, such as miastenic and Good syndrome and other immunological and paraneoplastic disorders. The principal treatment of these patients is chemotherapy with schedule containing cisplatin characterized by high response rates (60%). Unfortunately some patients do not respond at all and most patients do not achieve long-lasting remission. For these patients have not other therapeutic chances at the moment. There are few data of the efficacy of anti-angiogenetic drugs in TET but new knowledges are emerging on the potential use of this class of drugs in patients with TET on the basis of laboratory and preclinical translational findings. Materials and methods we investigated the expression of Vascular Endothelial Growth Factor (VEGF) and its receptors (VEGFR1, 2 and 3) in 200 TET arranged in Tissue Micro Array (TMA). We observed both histotype distribution and modulation of angiogenetic factors (both VEGFRs and VEGFs) in TET. Results we observed that, when compared with the low-grade counterpart, high grade TET (B2, B3 and Carcinomas) contained significantly higher numbers of VEGFA, VEGFC, VEGFD, VEGFR1 and VEGFR2 expressing tumor cells. In addition, in high grade TET, strong positive correlations between staining for VEGFA and those for all other markers were found. In the same tumors, VEGFC staining was not associated with VEGFR1, VEGFR3 and PDGFRB staining and no correlation was obtained between VEGFD and VEGFR1 or VEGFR3 staining. The co-expression in epithelial cells of growth factors and their receptors suggests the presence of autocrine mechanisms in TET. Conclusions according to our data VEGFs and VEGFRs in TET are potential targets of anti-angiogenesis drugs. Further studies are needed to investigate the potential role of anti-angiogenetic agents. Disclosure All authors have declared no conflicts of interest.

S100A13 is a new angiogenic marker in human melanoma

Angiogenesis is critical in melanoma progression and metastasis and relies on the synthesis and release of proangiogenic molecules such as vascular endothelial growth factor (VEGF)-A and fibroblast growth factors (FGFs). S100A13 is a small calcium-binding protein that facilitates the release of FGF-1, the prototype of the FGF family. S100A13 is upregulated in astrocytic gliomas, in which it correlates with VEGF-A expression, microvessel density and tumor grading, and promotes a more aggressive, invasive phenotype in lung cancer-derived cell lines. To investigate the involvement of S100A13 in human cutaneous melanoma, we analyzed a series of 87 cutaneous melanocytic lesions: 14 common acquired melanocytic nevi, 14 atypical, so-called ‘dysplastic’ nevi, 45 melanomas (17 radial growth phase and 28 vertical growth phase) and 14 melanoma metastases. Main clinical and pathological features, including histotype, Breslow thickness, Clark's level and outcome were recorded. Microvessel density was determined with CD105/endoglin staining. Semiquantitative determination of S100A13, FGF-1 and VEGF-A protein expression was obtained by immunostaining. Quantification of S100A13 mRNA was achieved by real-time PCR. We found that S100A13 was expressed in melanocytic lesions; compared with benign nevi, S100A13 protein expression was significantly upregulated in melanomas (P=0.024), in which it correlated positively with the intensity of VEGF-A staining (P=0.041) and microvessel density (P=0.007). The level of expression of S100A13 mRNA also significantly increased with progression of disease, from radial growth phase (0.7±0.7) to vertical growth phase (3.6±3.1) to metastases (7.0±7.0) (P<0.001). Furthermore, S100A13 mRNA correlated positively with VEGF-A (P=0.023), TNM stage (P=0.05), risk of relapse (P=0.014) and status at follow-up (P=0.024). In conclusion, S100A13 is expressed in melanocytic lesions when the angiogenic switch occurs and it may cooperate with VEGF-A in supporting the formation of new blood vessels, favoring the shift from radial to vertical tumor growth. Therefore, S100A13 may represent a new angiogenic and prognostic marker in melanoma.

Comparative Analysis of Vascular Endothelial Growth Factor-A, C, D Expression in Colorectal Cancer with Liver Metastasis

Purpose: We aimed to investigate the correlations between expressions of angiogenic cytokines VEGF-A, C, D of primary colorectal cancer and liver metastasis. Methods: We examined paraffin-embedded primary colorectal cancer tissue from 45 patients who had liver resection due to colorectal liver metastasis (metastasis group) and 37 patients who had surgical resection due to colorectal cancer only (control group). In the control group, local recurrence and distant metastasis had not occurred. Immunohistochemical staining for VEGF-A, C and D was performed. We analysed the correlations between expression of VEGF-A, C and D in primary colorectal cancer tissues and clinicopathologic parameters. Results: VEGF-A expressions of primary colorectal carcinoma were not different between the two groups. VEGF-C was more frequently expressed in the metastasis group (P=0.008) but VEGF-D was more expressed in the control group (P=0.003). Patients with VEGF-C negative and VEGF-D positive expression were predominant in the control group (P=0.020). Tumor location, T stage, lymph node metastasis and tumor differentiation were not related with the expressions of VEGF-A, C, D but only preoperative CEA was positively correlated with VEGF-A and C expression. Conclusion: Expressions of VEGF-C in primary tumor were more frequent in metastatic colorectal cancer and expressions of VEGF-D were more frequent in nonmetastatic colorectal cancer. More large-scale prospective studies for VEGF-C and D expression in colorectal cancer are necessary.

Pulmonary Angiogenesis in a Rat Model of Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS), defined as intrapulmonary vasodilation, occurs in 10%-30% of cirrhotics and increases mortality. In a rat model of HPS induced by common bile duct ligation (CBDL), but not thioacetamide (TAA)-induced nonbiliary cirrhosis, lung capillary density increases, monocytes accumulate in the microvasculature, and signaling factors in the angiogenesis pathway (Akt and endothelial nitric oxide synthase [eNOS]) are activated. Pentoxifylline (PTX) directly decreases lung endothelial Akt and eNOS activation, blocks intravascular monocyte accumulation, and improves experimental HPS; we evaluated whether pulmonary angiogenesis develops in this model. TAA- and PTX-treated animals were evaluated following CBDL. Lung angiogenesis was assessed by quantifying factor VIII-positive microvessels and levels of von Willebrand factor (vWf), vascular endothelial cadherin (VE-cadherin), and proliferating cell nuclear antigen (PCNA). Angiogenic factors including phospho-Akt, phospho-eNOS, vascular endothelial growth factor (VEGF)-A, and phospho-VEGF receptor-2 (p-VEGFR-2) were compared and monocyte accumulation was assessed. Following CBDL, but not TAA exposure, rats developed HPS that was temporally correlated with increased numbers of lung microvessel; increased levels of vWf, VE-cadherin and PCNA; and activation of Akt and eNOS. Angiogenesis was accompanied by increased pulmonary VEGF-A and p-VEGFR-2 levels, with VEGF-A staining in accumulated intravascular monocytes and alveolar endothelial cells. Following CBDL, PTX-treated rats had reduced numbers of microvessels, reduced lung monocyte accumulation, downregulation of pulmonary angiogenic factors, and reduced symptoms of HPS. A specific increase in pulmonary angiogenesis occurs as experimental HPS develops, accompanied by activation of VEGF-A-associated angiogenic pathways. PTX decreases the angiogenesis, reduces the symptoms of HPS, and downregulates VEGF-A mediated pathways.

Lymphoma-Expressed VEGF-a, VEGFR-1, VEGFR-2, and Microvessel Density Are Not Predictive of Overall Survival in Follicular Lymphoma

Introduction: Microvessel density is predictive of survival in some hematopoietic malignancies, but vascularity and its association with prognosis varies markedly by diagnostic category and perhaps by treatment type. Reports on association of microvessel density with clinical outcomes in follicular lymphoma are conflicting. Vascular endothelial growth factor (VEGF) mediated signaling has at least two potential roles in lymphoma biology: potentiation of angiogenesis, and direct potentiation of lymphoma cell growth or survival via autocrine VEGF-receptor mediated signaling. A single study reports poorer overall survival with diffuse VEGF-A expression. We have assessed microvessel density and lymphoma cell and microvessel expression of VEGF-A and its receptors VEGFR-1 (flt-1) and VEGFR-2 (VPF, KDR) by immunohistochemistry in a large cohort of follicular lymphoma patients.Patients and Methods: 187 follicular lymphoma patients underwent an excisional lymph node biopsy prior to any treatment. The median age at diagnosis was 45 yrs, with a median follow-up of 8.8 yrs and 51 deaths. All but 6 patients had stage III/IV disease, 3 had stage I/II, and 3 were unknown. The histological grades are as follows: 112 grade 1, 65 grade 2, and 10 grade 3. FLIPI (follicular-lymphoma specific international prognostic index) scores were as follows: 33 low, 95 intermediate, 19 high, 40 unavailable. For their initial treatment regimen 120 patients received CVP +/− fludarabine; 42 others received a variety of other chemotherapeutic regimens; and 9 patients received rituximab.We separately enumerated extrafollicular and follicular CD34+ microvessels in two separate high power fields (hpf) of duplicate tissue microarray cores. Immunostains for VEGFR-1, VEGFR-2 and VEGF were scored as follows: >30% of lymphoma cells strongly staining, strong; 5–30% staining, or weak diffuse staining, weak; and < 5%, none. Additionally, tumor microvessels were scored as showing strong, weak, or no reactivity. The highest score obtained from the duplicate cores was reported.Results: As previously reported microvessel density was much higher in extrafollicular than in follicular areas (mean 6.5 vs 22 mvd/hpf, p = 7.31E-69), and was therefore assessed separately in the two compartments. Microvessel density did not vary by grade or FLIPI score. There was no association between microvessel density and VEGF-A expression. Microvessel density was not associated with overall survival, time from diagnosis to first treatment, or time from first treatment to second treatment.Lymphoma cell expression of VEGF-A and VEGFR-1, but not VEGFR-2, was significantly associated with grade: 22% of Grade 1, 40% of grade 2, and 60% of grade 3 follicular lymphomas showed strong VEGF-A staining (chi 9.95, p < 0.007); 43% of Grade 1, 62% of Grade 2, and 90% of grade 3 follicular lymphomas showed strong VEGFR-1 staining (chi = 12.0, p < 0.003). VEGFR-2 was highly expressed in all grades: 72% of grade 1, 80% of grade 2, and 90% of grade 3 follicular lymphomas. There was no relationship between VEGF or VEGFR expression and overall survival, time to treatment, or FLIPI score.In addition to lymphoma cell reactivity, we noticed strong reactivity for VEGF and VEGFR in tumor microvessels in many cases, particularly in the highly vascularized extrafollicular areas. Strong VEGF-A reactivity was present in 29%, VEGFR-1 in 78%, and VEGFR-2 in 94% of cases in the microvasculature. Vessel VEGF-A reactivity correlated with vessel VEGFR-1 (chi 26.6, p = 2.5E−07) and VEGFR-2 (chi 13.8, p = 0.0006). There was no association with grade or FLIPI score. Interestingly, microvessel VEGFR-1 reactivity was associated with worse overall survival (median 130 vs 92 months, z = 1.98, z = 0.048) and this association was independent of FLIPI score and grade on multivariate analysis (z=1.994, p = 0.046).Conclusions: VEGF-A and its receptors VEGFR-1 and VEGFR-2 are highly expressed in follicular lymphoma cells and their expression increases with grade. VEGF-A and its receptors are also often coexpressed in follicular lymphoma microvasculature. There is a borderline statistically significant association between microvessel VEGFR-1 reactivity and overall survival in this study; however given the number of markers assessed, the significance of this finding is unclear. Neither microvessel density nor lymphoma cell expression of VEGF-A, VEGFR-1, or VEGFR-2 is predictive of overall survival.

Localisation of members of the vascular endothelial growth factor (VEGF) family and their receptors in human atherosclerotic arteries

Background: Vascular endothelial growth factor (VEGF) mediates endothelial cell mitogenesis and enhances vascular permeability. The existence of single or multiple VEGF isoforms and receptors suggests that these proteins may have...

Expression of vascular endothelial growth factors and their receptors in and around intracranial arteriovenous malformations.

The precise mechanisms responsible for the development and growth of intracranial arteriovenous malformations (AVMs) remain unclear, but it has been hypothesized that vascular endothelial growth factors (VEGFs) might be involved in their pathogenesis. The aim of this study was to examine immunohistochemically the presence of the VEGF family (VEGF-A to -D) and their receptors (Flt-1, Flk-1, and Flt-4) in the surgically resected AVM nidus. The AVM nidus was surgically obtained from 31 patients with AVMs (mean age, 40.5 yr, range 13-73 yr). The mean size of the nidus was 31.6 mm (range, 15-60 mm). Formalin-fixed, paraffin-embedded specimens were stained immunohistochemically by the labeled streptavidin-biotin method with antibodies against VEGF-A to -D, as well as Flt-1, Flk-1, and Flt-4. Positive staining for VEGF-A to -D was observed in the endothelial cells of the abnormal vessels involved in the AVM nidus and in the cytoplasm of astroglia surrounding it. Samples from 30 (96.8%) of 31 patients stained positive for VEGF-A, 4 (9.7%) for VEGF-B, 17 (54.5%) for VEGF-C, and 16 (51.6%) for VEGF-D. Flt-1, Flk-1, and Flt-4 were also positive chiefly, but not exclusively, in the cytoplasm of vascular endothelium and smooth muscle cells of the vascular wall. With regard to VEGF receptors, it was found that among the 31 patients studied, 19 (61.3%) were immunohistochemically positive for Flt-1, 6 (19.4%) for Flk-1, and 19 (61.3%) for Flt-4. A comparison of mean nidus size and average age at operation revealed significant differences between patients positive for VEGF-C, VEGF-D, Flt-1, or Flt-4. In contrast, there were no significant differences in nidus size and age in patients positive for VEGF-A, VEGF-B, and Flk-1. These results strongly suggest a possible contribution of the VEGF-VEGF receptor system to the growth of intracranial AVMs.