Angiogenesis In Human Breast Cancer Research Articles

Up-regulation of cyclooxygenase-2 gene expression correlates with tumor angiogenesis in human breast cancer

Objective: To study the relationship between cyclooxygenase-2 (COX-2) expression and tumor angiogenesis in human breast cancer. Methods: Archival primary breast carcinomas (n=62), adjacent ductal carcinomain situ (DCIS, n=13) and DCIS alone (n=5) were analyzed for COX-2 and VEGF expression by immunohistochemistry using specific monoclonal antibodies. Microvessel density (MVD) was also examined the using CD34 staining. Results: A significant correlation was found between COX-2 and VEGF expression (P<0.01). Both COX-2 and VEGF were significantly correlated with MVD (P<0.05) andP<0.01, respectively). COX-2 and VEGF genes were overexpressed in tumor specimens as compared with normal epithelia. Conclusion: COX-2 is related to tumor angiogenesis in breast cancer. It is likely that VEGF is one of the most important mediators of the COX-2 angiogenic pathway.

Cyclo-oxygenase-2 (COX-2) mRNA expression correlates with progesterone receptor positivity in human breast cancer.

We previously presented evidence showing that cyclo-oxygenase 2 (COX-2) plays an important role in mammary carcinogenesis and angiogenesis in human breast cancer. The present study aims to compare COX-2 mRNA expression with hormone receptor status, S-phase fraction, telomerase activity, and DNA ploidy in human breast cancer. Total cellular RNA was extracted from frozen breast tissue samples according to standard methodology. The mRNA copy numbers for COX-2 were determined in 18 infiltrating carcinomas using quantitative RT-PCR and TaqMan methodology. The oestrogen receptor (ER) and progesterone receptor (PgR) status was determined using the ligand-binding technique (ER+ = > 3 fmol/mg, PgR+ = > 5 fmol/mg). We also determined DNA ploidy status (diploid or aneuploid), S-phase fraction (< 6% = low, 6-10% = intermediate, > 10% = high), and telomerase activity (total protein generated by TRAP assay). The median COX-2 mRNA copy number per micro g of RNA was 126 713 (range = 15 717-2 022 050). COX-2 expression was significantly associated with PgR positivity (p = 0.013). The association between COX-2 and DNA diploidy failed to reach a statistical significance (p = 0.085). No significant association was detected between COX-2 and S-phase fraction, ER status, or telomerase activity. COX-2 mRNA expression is associated with PgR positivity in human breast cancer. This observation is consistent with the hypothesis that COX-2 upregulates aromatase activity.

Cyclo-oxygenase-2 (COX-2) mRNA expression correlates with progesterone receptor positivity in human breast cancer

SUMMARYBackground: We previously presented evidence showing that cyclo-oxygenase 2 (COX-2) plays an important role in mammary carcinogenesis and angiogenesis in human breast cancer. The present study aims to compare COX-2 mRNA expression with hormone receptor status, S-phase fraction, telomerase activity, and DNA ploidy in human breast cancer.Methods: Total cellular RNA was extracted from frozen breast tissue samples according to standard methodology. The mRNA copy numbers for COX-2 were determined in 18 infiltrating carcinomas using quantitative RT-PCR and TaqMan methodology. The oestrogen receptor (ER) and progesterone receptor (PgR) status was determined using the ligand-binding technique (ER+ = >3 fmol/mg, PgR+ = >5fmol/mg). We also determined DNA ploidy status (diploid or aneuploid), S-phase fraction (<6% = low, 6-10% = intermediate, > 10% = high), and telomerase activity (total protein generated by TRAP assay).Results: The median COX-2 mRNA copy number per ug of RNA was 126 713 (range = 15717-2022050). COX-2 expression was significantly associated with PgR positivity (p = 0.013). The association between COX-2 and DNA diploidy failed to reach a statistical significance (p = 0.085). No significant association was detected between COX-2 and S-phase fraction, ER status, or telomerase activity.Conclusions: COX-2 mRNA expression is associated with PgR positivity in human breast cancer. This observation is consistent with the hypothesis that COX-2 upregulates aromatase activity.

The association between cyclo-oxygenase-2 expression and cell proliferation and angiogenesis in human breast cancer

The association between cyclo-oxygenase-2 expression and cell proliferation and angiogenesis in human breast cancer

Tumor Growth of FGF or VEGF Transfected MCF-7 Breast Carcinoma Cells Correlates with Density of Specific Microvessels Independent of the Transfected Angiogenic Factor

We have previously shown that fibroblast growth factor (FGF)-1-, FGF-4-, or vascular endothelial growth factor (VEGF/VPF)-transfected MCF-7 breast carcinoma cells growing as tumors in nude mice are tamoxifen resistant and/or estrogen independent. These transfectants provide opportunity for study of in situ tumor-induced angiogenesis promoted by the individual angiogenic factors under growth-promoting versus growth-inhibiting hormonal conditions. In the present study, vessels in tumors harvested at varying times after tumor cell injection were immunohistochemically highlighted and vessel morphology and topography were scored on a scale of 0 to 4 by blinded observers. In tumors produced by all cell lines under all growth-promoting hormonal conditions, there was significantly increased abundance (P < 0.05) of edge-associated and intratumor microvessels, but not of stromally located microvessels, when compared with tumor nodules harvested under growth-inhibiting conditions, regardless of the identity of the angiogenic factor or the hormonal treatment. Image analysis of bromodeoxyuridine (BrdU)-labeled nuclei of tumors produced by all cell lines under all hormonal conditions harvested at early time points showed that mean labeling indices were highest for hormonal conditions that produced the most robust growth in that particular cell line, implying that a high BrdU labeling index is a predictor of future tumor growth in individual tumors. These results confirm previous studies that established the importance of neovascularization for tumor growth and provide validation for use of these cell lines to study the process of angiogenesis in vivo. Study of gene expression in endothelial cells in edge-associated or intratumor vessels using this model might reveal mechanisms important in tumor-induced angiogenesis in human breast cancer.

Clinical significance of angiogenic factors in breast cancer.

Growth, progression, and metastasis of breast cancer, as well as of most of the other tumors, are angiogenesis-dependent processes. Several pro-angiogenic growth factors and endogenous inhibitors of angiogenesis have been identified and sequenced, and experimental studies suggest that angiogenic activity of a tumor may result from downregulation of inhibitors of angiogenesis or up-regulation of endothelial growth factors. The mechanisms leading to the alteration of the balance between positive and negative modulators of angiogenesis are only partially known. We are at the beginning of research to identify the more active angiogenic factors in human breast cancer, and little information is presently available on their clinical significance. Preliminary results suggest that among the known angiogenic peptides, both vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor / thymidine phosphorylase (PD-ECGF/TP) have promising prognostic and, perhaps, predictive value. No data are available on the clinical value of co-determination of positive and negative regulators of angiogenesis to look at the angiogenic balance of each single tumor. Only a few studies have assessed the role of endogenous inhibitors of angiogenesis in human breast cancer, with results available only on thrombospondin-1 and -2 (TSP-1, -2). Finally, the determination of some integrins such as alpha6 and alphavbeta3 and of some other endothelial-adhesion molecules seems to be of potential prognostic value. Recognizing which are the more biologically active positive and negative angiogenic factors is the key for the identification not only of new prognostic markers but also of targets for antiangiogenic therapy in human breast cancer.

Clinical significance of the determination of angiogenesis in human breast cancer: Update of the biological background and overview of the vicenza studies

Clinical significance of the determination of angiogenesis in human breast cancer: Update of the biological background and overview of the vicenza studies

Immunocytochemical analysis of MDM2 protein expression and its relevance to tumor angiogenesis in primary breast cancer

MDM2 once-protein is known to be involved in the inactivation of p53 and RE functions. We have investigated the expression of MDM2 protein in breast cancer by immunocytochemical analysis. Out of 103 primary tumors 39 (38%) showed positive nuclear staining of MDM2, although its gene amplification was infrequent. There was no correlation between MDM2 expression and various clinicopathological factors. However, MDM2 expression was significantly associated with expression of angiogenesis factors including vascular endothelial growth factor and platelet-derived endothelial cell growth factor. Anti-endothelial immunostaining demonstrated a correlation between MDM2 expression and the increment of intratumoral microvessel density. It is suggested that altered MDM2 protein expression might be involved in the promotion of angiogenesis in human breast cancer.

In situ detection of tissue factor in vascular endothelial cells: correlation with the malignant phenotype of human breast disease.

Expression of tissue factor (TF) in the endothelium has been observed only rarely in human disease and has been thought to be elaborated on the surface of vascular endothelial cells (VECs) in vitro as an artifact of tissue culture. Using monoclonal antibodies and a novel probe for functional TF, we have localized TF to the VECs (and tumor cells) within the tumors of seven patients with invasive breast cancer but not in the VECs (or tumor cells) of benign tumors from ten patients with fibrocystic disease of the breast. The potent procoagulant TF was shown to be a marker of the initiation of angiogenesis in human breast cancer. Further evidence that the TF was the demonstration of a similar distribution of cross-linked fibrin only in the VECs of the malignant tumors. We interpret these data as further support for the concept that tumor cells can activate nearby VECs and regulate blood vessel growth in vivo. Large clinical pathologic studies will be necessary to determine whether TF is a useful marker for the "switch" to the angiogenic phenotype" in human breast disease and/or correlates with the thromboembolic complications of breast cancer.

Expression of platelet‐derived endothelial cell growth factor/thymidine phosphorylase in human breast cancer

We have investigated the expression of platelet-derived endothelial-cell growth factor/thymidine phosphorylase (PD-ECGF/dThdPase) in human breast-cancer tissues by the immunocytochemical method using anti-PD-ECGF/dThdPase monoclonal antibody. Out of 100 invasive-ductal-carcinoma tissue samples, 39 (39%) were evaluated as PD-ECGF/dThdPase-positive. The expression of PD-ECGF/dThdPase was identified mainly in the cytoplasma of tumor cells. The expression of PD-ECGF/dThdPase was significantly associated with the microvessel density assessed by immunostaining to factor-VIII-related-antigen (p < 0.05). However, there was no correlation between expression of PD-ECGF/dThdPase and menopausal status, tumor size, axillary lymph-node metastases, hormone-receptor status, epidermal-growth-factor receptor, or erb-B-2-protein and p53-protein expression. We suggest that expression of PD-ECGF/dThdPase plays an important role in the promotion of angiogenesis in human breast cancer.