2321

FLT1

fms-related tyrosine kinase 1;FLT1;fms-related tyrosine kinase 1

fms-like tyrosine kinase 1|fms-related tyrosine kinase 1 (vascular endothelial growth factor/vascular permeability factor receptor)|tyrosine-protein kinase FRT|tyrosine-protein kinase receptor FLT|vascular endothelial growth factor receptor 1|vascular per

13q12

protein-coding

PURPOSE Preclinical studies indicate that metronomic chemotherapy is antiangiogenic and synergistic with other antiangiogenic agents. We designed a phase I/II study to evaluate the safety and activity of adding dalteparin and prednisone to metronomic cyclophosphamide and methotrexate in women with measurable metastatic breast cancer (MBC). PATIENTS AND METHODS Patients received daily dalteparin and oral cyclophosphamide, twice-weekly methotrexate, and daily prednisone (dalCMP). The primary study end point was clinical benefit rate (CBR), a combination of complete response (CR), partial response (PR), and prolonged stable disease for > or = 24 weeks (pSD). Secondary end points included time to progression (TTP), duration of response, and overall survival (OS). Biomarker response to treatment was assessed by using plasma vascular endothelial growth factor (VEGF) and soluble VEGF receptors (sVEGFRs) -1 and -2. Results Forty-one eligible patients were accrued. Sixteen (39%) had no prior chemotherapy for MBC; 15 (37%) had two or more chemotherapy regimens for MBC. Toxicities were minimal except for transient grade 3 elevation of liver transaminases in 11 patients (27%) and grade 3 vomiting in one patient (2%). One patient (2%) had CR, six (15%) had PR, and three (7%) had pSD, for a CBR of 10 (24%) of 41 patients. Median TTP was 10 weeks (95% CI, 8 to 17 weeks), and median OS was 48 weeks (95% CI, 32 to 79 weeks). VEGF levels decreased but not significantly, whereas sVEGFR-1 and -2 levels increased significantly after 2 weeks of therapy. There was no correlation between response and VEGF, sVEGFR-1, or sVEGFR-2 levels. CONCLUSION Metronomic dalCMP is safe, well tolerated, and clinically active in MBC.

OBJECTIVE: To investigate the relationship between the expression of vascular endothelial growth factor (VEGF) and fms-like tyrosine kinase (Flt-1) mRNA and tumor progression, microvessel density and survival time in gastric carcinoma. METHODS: In situ hybridization and immunohistochemical techniques were used to detect the gene expression of VEGF, Flt-1 and CD34 in 118 gastric carcinoma specimens. RESULTS: In situ hybridization revealed that positive expression rates of VEGF and Flt-1 mRNA in gastric carcinoma were 54.24% and 55.9% respectively. There was a significant correlation between the expression of VEGF and Flt-1 mRNA and growth pattern, the depth of tumor invasion, vessel invasion, lymph node and distant metastasis (P < 0.01). The mean tumor microvessel densities (MVD) in patients of stage T3-T4 or those with vessel invasion, lymph node and distant metastases were significantly higher than those of stage T1-T2 and without metastases (P < 0.01). MVD value was correlated with the expression levels of VEGF and Flt-1 mRNA (P < 0.01). The mean survival time and survival rate of patients with positive mRNA expression and mean MVD value >or=54.9/mm2 were significantly lower than those of patients with negative mRNA expression and mean MVD value < 54.9/mm2. CONCLUSIONS: The expression of VEGF and Flt-1 can promote tumor angiogenesis and contribute to tumor invasion and metastasis in gastric carcinoma. VEGF and Flt-1 may serve as valuable indicators of biological behaviour, prognosis and target of gene therapy in gastric carcinoma.

PURPOSE: Recent studies of cancer metastasis have focused on the role of premetastatic gene expression and circulating tumor cells. We did a blind prospective study in gastric cancer to assess the significance of isolated tumor cells (ITC) and to test the hypothesis that vascular endothelial growth factor receptor-1 (VEGFR-1) is expressed within the bone marrow at tumor-specific, premetastatic sites. EXPERIMENTAL DESIGN: Both bone marrow and peripheral blood samples from 810 gastric cancer patients were collected at the Central Hospital, National cancer Center (Tokyo, Japan). The samples were transferred to Kyushu University Hospital (Beppu, Japan) where they were analyzed by quantitative real-time reverse transcription-PCR for three epithelial cell markers, carcinoembryonic antigen, cytokeratin-19, and cytokeratin-7, as well as VEGFR-1. RESULTS: ITCs were observed in peripheral blood and bone marrow even in early stages of gastric cancer. The frequency of ITC in bone marrow was significantly associated with the stage of disease by ANOVA (P < 0.01). Gastric cancer metastasized when ITCs were observed in the presence of VEGFR-1. In the 380 patients who were ITC negative and showed low VEGFR-1 expression, synchronous (at the time of surgery) and heterochronous (recurrent) metastases were not observed. CONCLUSIONS: ITCs circulate even in early stages of disease. Furthermore, elevated expression of VEGFR-1 facilitates the establishment of hematogenous metastases in gastric cancer. This study indicates that the simultaneous presence of ITC and VEGFR-1 expression at premetastatic sites is clinically significant for disease progression.

OBJECTIVE: To study the expression of vascular endothelial growth factor (VEGF) and both the Flt-1 and KDR high affinity VEGF receptors in human laryngeal carcinoma cells and its significance. METHOD: In this study, we investigated the expression of VEGF mRNA and both the Fit-1 mRNA and KDR mRNA high affinity VEGF receptors in human laryngeal carcinoma cells using techniques of semi-quantify RT-PCR. RESULT: It was showed that the expression level of VEGF mRNA was significantly increased in human laryngeal carcinoma cells as compared with the normal cells, Hacat cells (P <0.05), and there was the high expression level of Flt-1 mRNA in the Hep-2 cells, but not KDR mRNA. CONCLUSION: These data raise the possibility that VEGF and its receptors many play key roles in the growth, invasion and metastasis of human laryngeal carcinoma cells through either a paracrine or an autocrine mechanism.

OBJECTIVES: To examine whether or not vascular endothelial growth factor (VEGF) and its receptors were expressed in hepatocellular carcinoma cell lines with various metastatic potentialities. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR), enzyme linked immunosorbent assay (ELISA) and Western blot were employed to study the expressions of VEGFR-1, VEGFR-2, VEGF-A and VEGF-B in four hepatocellular carcinoma cell lines MHCC97-H, MHCC97-L, SMMC7721 and HepG-2 and one normal liver cell line L-02. RESULTS: Three hepatocellular carcinoma cell lines (MHCC97-H, MHCC97-L, SMMC7721) expressed VEGFR-1 mRNA and their proteins. The expression level of VEGFR-1 in MHCC97-H was higher than that in MHCC97-L (P less than 0.05) and the expression level of VEGFR-1 in MHCC97-L was higher than that in SMMC7721 (P less than 0.05). No expression of VEGFR-1 was found in HepG-2 or L-02. All four hepatocellular carcinoma cell lines and the L-02 cell line expressed VEGFR-2 mRNA and the protein, as well as the VEGFR-1 ligands VEGF-A and VEGF-B. The expression level of VEGFR-2 in all tested hepatocellular carcinoma cell lines and normal liver cell line L-02 showed no significant differences (P more than 0.05). CONCLUSION: VEGFR-1 was expressed in 4 hepatocellular carcinoma cell lines with various metastatic potentialities. The expression levels appeared to be positively correlated with the potentialities of metastasis of the hepatocellular carcinoma cell lines. VEGFR-1 may relate to the invasiveness and metastatic potential of the hepatocellular carcinoma.

Bone marrow-derived cells, which are recruited to peripheral tissues, have been shown to play a major role as angiogenic factor supplier. Moreover, bone marrow-derived "hemangiocytes" through graded chemokines production, can function as the molecular hub for hematopoietic cytokine-induced neovascularization. Current focus on cancer metastasis has centered on the intrinsic factors regulating the cell autonomous homing of the tumor cells to the metastatic site : Bone marrow-derived cells expressing vascular endothelial growth factor receptor 1 can be mobilized into the circulation due to growth factors released by the primary tumor. These cells cluster at distant sites, "the premetastatic niche" , where they set up a microenvironment ideal for tumor cells to seed, thereby completing the metastatic spread. Focus on the early cellular and molecular events in cancer infiltration, metastasis and proliferation will likely lead to new approaches to detect and prevent metastasis at its earliest inception.

Pheochromocytoma (PHEO), a rare catecholamine producing tumor arising from the chromaffin cells, may occurs sporadically (76%-80%) or as part of inherited syndromes (20%-24%). Angiogenesis is a fundamental step in tumor proliferation and vascular endothelial growth factor (VEGF-A) is the most well-characterized angiogenic factor. The role of angiogenic markers in PHEO is not fully understood; investigations were therefore made to evaluate the expression of VEGF-A and its receptors in PHEO and correlate to clinical parameters. Twenty-nine samples of PHEO were evaluated for VEGF-A, VEGF receptor-1 (VEGFR-1) VEGFR-2 expression and microvessel density (MVD) by immunohistochemistry. Clinical data were reviewed in medical records. The mean age of patients was 38+/-14 years, and 69% were woman. VEGF-A, VEGFR-1 and VEGFR-2 staining were detected in nearly all PHEO samples. No significant correlation was observed between VEGF-A, VEGFR-1, VEGFR-2 expression or MVD and age at diagnosis, tumor size or sporadic and hereditary PHEO. However, the levels of expression of these molecules were significantly higher in malignant PHEO samples (p=0.027, p=0.003 and p=0.026, respectively).VEGF-A and its receptors were shown to be up-regulated in malignant PHEO, suggesting that these molecules might be considered as therapeutic targets for unresectable or metastatic tumors.

metastatic renal cell carcinoma (RCC) associates with overproduction of vascular endothelial growth factor (VEGF) due to the mutation/inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene. Herein we demonstrate that implantation of human RCC tumor cells into athymic nude mice promotes the appearance of VEGF receptor 1 (VEGFR1)/CD11b double-positive myeloid cells in peripheral blood. Avastin-mediated VEGF neutralization was capable of significantly reducing the numbers of circulating VEGFR1+ myeloid cells. Conversely, up-regulation of VEGFR1 by myeloid cells could also be achieved in vitro by coculturing bone marrow cells with RCC-conditioned medium or by short-term exposure of naive myeloid cells to oxidative stress. Treatment of myeloid cells with H2O2, lipid peroxidation product 4-hydroxy-2(E)-nonenal, or an inhibitor of thioredoxin reductase all resulted in increased expression of VEGFR1. Furthermore, after exposure to oxidative stress, myeloid cells acquire immunosuppressive features and become capable of inhibiting T cell proliferation. Data suggest that tumor-induced oxidative stress may promote both VEGFR1 up-regulation and immunosuppressive function in bone marrow-derived myeloid cells. Analysis of tumor tissue and peripheral blood from patients with metastatic RCC revealed that VEGFR1+ cells can be also found in cancer patients. Restoration of immunocompetence in metastatic RCC patients by pharmacological elimination of VEGFR1+ cells may have a significant impact on the therapeutic efficacy of cancer vaccines or other immune-based therapies.

BACKGROUND: There are no validated markers that predict outcome in metastatic renal cell cancer (mRCC) patients treated with sunitinib. Recently, single nucleotide polymorphism (SNP) rs9582036 in VEGFR1 has been proposed as a predictor of progression-free survival (PFS) and overall survival (OS) to bevacizumab in patients with pancreatic cancer and rs7993418 in VEGFR1 as predictor for PFS in mRCC-patients treated with bevacizumab. Here, we aim to study the impact of these SNPs in mRCC patients treated with sunitinib. METHODS: We included patients with mRCC treated in 15 institutions in France and Belgium. Patients received sunitinib as first-line targeted therapy. We assessed response, time-to-tumor progression (TTP), OS, and clinical and biochemical parameters associated with outcome. We genotyped rs9582036 and rs7993418 as well as three other surrounding SNPs in VEGFR1: rs9554320, rs9554316 and rs9513070. Association between SNPs and treatment outcome were studied by univariate analysis and by multivariate Cox regression using relevant clinical factors associated with TTP and OS as covariates. FINDINGS: Ninety-one patients were included. We found that mRCC patients with the CC-variant in rs9582036 in VEGFR1 have a poorer response rate (RR) (0% vs. 46%, p = 0.028), a poorer PFS (10 vs. 18 months, p = 0.033 on univariate and 0.06 on multivariate analysis) and a poorer OS (14 vs. 31 months, p = 0.019 on univariate and 0.008 on multivariate analysis) compared to patients with the AC- and AA-genotypes. mRCC patients with the AA-variant in rs9554320 in VEGFR1 have a poorer PFS (12 vs. 21 months, p = 0.0066 on univariate and 0.005 on multivariate analysis) and a poorer OS (22 vs. 34 months, p = 0.019 on univariate and 0.067 on multivariate analysis) compared to patients with the AC- and CC-genotypes. Interpretation. mRCC patients with the CC-genotype in VEGFR1 SNP rs9582036 have a poorer response rate, PFS and OS when treated with sunitinib. These findings are in agreement with the association of rs9582036 and outcome observed in bevacizumab treated pancreatic cancer patients. Prospective validation of this SNP is warranted.

OBJECTIVE: Vascular endothelial growth factor (VEGF) and VEGF receptor 1 (VEGFR1) are known to be related to thyroid tumorigenesis. The aim of the study was to examine the expressions and serum levels of VEGF, VEGFR1, IGF1, and IGF1 receptor (IGF1R) in patients with differentiated thyroid carcinoma (DTC) compared with patients with nodular goiter (NG). METHODS: We examined 39 patients with DTC who had a clinical history of at least 2 years and compared them with 25 patients who had a pathological diagnosis of NG after thyroidectomy. Serum VEGF, VEGFR1, and IGF1 levels were measured in both patient groups. The expressions of VEGF, VEGFR1, IGF1, and IGF1R were analyzed by the immunohistochemical method in the paraffin blocks of patients' thyroidectomy samples of the patients. RESULTS: The immunostainings scores for VEGF, VEGFR1, IGF1, and IGF1R were found to be higher in patients with DTC than in those with NG. Only VEGFR1 expression was related to lymph node metastasis at the time of surgery. None of the expressions were related to the long-term prognosis of the patients. Serum VEGF was found to be higher in patients with progressive DTC than in patients in clinical remission. CONCLUSION: The expressions of VEGF and VEGFR1 were shown to be correlated with the expression of IGF1 and IGF1R. VEGFR1 expression may be an important index for the presence of lymph node metastasis at the time of thyroidectomy. Increased serum levels of VEGF may reflect disease recurrence in DTC.