Quantitation of vascular endothelial growth factor mRNA levels in human breast tumors and metastatic lymph nodes

Vascular endothelial growth factor mRNA levels quantified by reverse transcription-polymerase chain reaction in microdissected breast carcinoma tissues are correlated with histological type and grade of both invasive and intraductal components

In breast cancer, vascular endothelial growth factor (VEGF) is a prognostic factor, but the relationship of VEGF mRNA levels with various parameters or tumor progression is unclear. VEGF mRNA levels were measured in 48 cases of invasive ductal carcinoma by using laser capture microdissection and quantitative reverse transcription-polymerase chain reaction (RT-PCR). The mean VEGF mRNA levels were compared among different histological types and grades in 41 and 29 samples of invasive and intraductal components, respectively. VEGF mRNA levels were always higher in cancerous cells than in non-cancerous cells, but mean VEGF mRNA levels were not significantly different between invasive component (3.24 +/- 3.18-fold the value of non-cancerous tissue) and intraductal component (4.14 +/- 4.43-fold). They were higher in papillotubular type than in other types, and higher in grade 2 carcinomas than in grade 3 carcinomas of invasive component, and higher in comedo type than in other types of intraductal component. Mean VEGF mRNA levels were higher in the VEGF-immunopositive group than in the VEGF-immunonegative group. There was no correlation between VEGF mRNA levels and tumor size, nodal status, or hormone receptor status. VEGF expression may play an important role in the development of both invasive and intraductal carcinoma components, especially those carcinoma components of less aggressive histological features.

Correlation of blood-glucose control with oxidative metabolites in plasma and vitreous body of diabetic patients

PURPOSE

In diabetes hyperglycemia and other mechanisms lead to the production of oxidative metabolites that can enhance the production of growth factors, leading to increased proliferative activity. Strict blood-glucose control reduces the progression of retinopathy better than standard control. This study investigated patients with diabetic retinopathy for evidence of oxidative metabolites in plasma and the vitreous body, correlating these values with blood-glucose control.

METHODS

The study comprised 136 patients suffering from proliferative diabetic retinopathy. They were grouped according to their mean glycosylated hemoglobin value for the last 9-12 months. Patients with values < or = 10% (mean 8.7%; n=64) were considered strict glucose control patients, those with values > 10% (mean 12.8%; n=72) were considered standard glucose control patients. Lipid peroxides were determined in blood plasma and the vitreous body by two methods (thiobarbituric acid reactive substances and malondialdehyde-like substances). If present, retinal traction with fibrovascular proliferations (>2 disk areas) was quantified and served as an indicator of proliferative activity.

RESULTS

Patients with strict blood-glucose control had significantly (p < 0.01) lower lipid peroxide values in plasma and the vitreous body than standard glucose control patients. These latter had significantly (p<0.01) higher rate of fibrovascular proliferation (50%) than strict glucose control patients (9. 7%).

DISCUSSION

Strict blood-glucose control leads to reduced oxidative tissue damage both systemically and locally in the eye, and reduced proliferative activity. Oxidative metabolites can stimulate proliferation by increasing the amounts of different growth factors an cytokines such as vascular endothelial growth factor. Thus, it can be speculated that in hyperglycemia the relative increase of oxidative metabolites contributes both to damage of retinal vessels and to more pronounced proliferative activity in diabetic retinopathy.

Chemiluminometric determination of tissue polypeptide antigen (TPA), cancer antigen 15-3 (CA 15-3), carcinoembryonic antigen (CEA) in comparison with vascular endothelial growth factor (VEGF) in follow-up of breast cancer

Vascular endothelial growth factor (VEGF), tissue polypeptide antigen (TPA), cancer antigen 15-3 (CA 15-3) and carcinoembryonic antigen (CEA) were measured in 314 sera of breast cancer patients and in 58 sera of women without breast cancer. VEGF was determined using a sandwich enzyme immunoassay technique (ELISA) and the tumour markers TPA, CA 15-3 and CEA with an immunoluminometric assay (ILMA). The breast cancer patients were staged according to the TNM classification stages 0-IV (by UICC) in patient groups with a compatible prognosis. Median and range of each stage were investigated. The cut-off values (95th and 97.5th percentile of control group) of VEGF, TPA, CA15-3 and CEA were determined; sensitivities for each parameter and for all combinations of two parameters were investigated for these cut-offs and the receiver operating characteristic (ROC) curves were calculated. The differences between the control group and stages 0-3 were shown to be non-significant for CA 15-3 and CEA but significant for VEGF and TPA. Significant differences were found in stage 4 for VEGF and all three markers. The increase in sensitivity of VEGF from stage 0 to stage 3 and the decrease from stage 3 to stage 4 can be interpreted based on the role of VEGF in the angiogenesis. The quantification of VEGF could give additional information for selecting patients for systemic adjuvant therapy.

Vascular endothelial growth factor A (VEGF-A) mRNA expression levels decrease after menopause in normal breast tissue but not in breast cancer lesions

We hypothesized that the regulation of microvascular functions and angiogenesis in breast tissue, a well known target of ovarian steroid action, is dependent on the hormonal exposure of the breast. Relative expression levels of VEGF-A (vascular endothelial growth factor A), a putative key regulator of angiogenesis in breast cancer, were analysed in the tumour and the adjacent non-neoplastic breast tissue of 19 breast cancer patients by quantitative reverse transcriptase polymerase chain reaction. In non-neoplastic breast specimens the expression levels of all detected VEGF-A-isoforms (189, 165, 121) were significantly higher in premenopausal compared to post-menopausal women (P = 0.02) and were inversely correlated with the patient's age (P = 0.006). In contrast, in cancerous tissues menopausal status had no influence on VEGF-A-expression levels. Benign and malignant tissues exhibited a similar expression pattern of VEGF-A-isoforms relative to each other. Thus, the regulation of the vasculature in normal breast tissue, as opposed to breast cancer tissue, appears to be hormonally dependent. Endogenous and therapeutically used hormonal steroids might, therefore, cause clinically relevant changes of the angiogenic phenotype of the human breast.

Microautoradiographic quantitation of vascular endothelial growth factor mRNA levels in human prostate specimens containing normal and neoplastic epithelium

Human prostate specimens commonly contain a spectrum of epithelial changes, including normal acinar and ductal structures, hyperplasia, intraepithelial neoplasia (dysplasia), and carcinoma. Since vascular endothelial growth factor (VEGF) expression is dependent on cell type and tissue microenvironment, meaningful quantitation of the levels of this mRNA in pathological specimens requires analysis at the microscopic level. Phosphorimage analysis of the binding of radiolabeled cRNA probes to tissue sections allows quantitation of mRNA levels, but the resolution is limited. Alternatively, emulsion autoradiography allows visualization of mRNA levels at cellular resolution, but quantitation is difficult. We have developed a method of quantitating steady state mRNA levels in tissue sections at the microscopic level, using autoradiography and quantitative image analysis. In this study, we describe the method and apply it to quantitation of VEGF mRNA in human prostate specimens. The VEGF mRNA level was low in nonepithelial stromal tissue (0.8 dpm/mm2), high in normal and benign hyperplastic epithelium (17-18 dpm/mm2), and significantly decreased in intraepithelial neoplasia (6.4 dpm/mm2) and in microacinar carcinoma that had invaded the stroma (3.5 dpm/mm2). Immunohistochemical staining detected VEGF protein in epithelial and stromal cells, with highest levels on the luminal surface of normal epithelium and in stromal cells, and lower levels in benign hyperplasia, intraepithelial neoplasia, and carcinoma. No correlation between VEGF expression in epithelium and nearby vessel density was observed. The results indicate a decrease in the steady state level of VEGF mRNA when prostate epithelial cells become transformed, escape the confines of glandular structure and invade the stroma, and suggest that the progression of prostatic carcinoma through the stages examined in this study is not associated with increased VEGF expression, in contrast to the elevated VEGF expression associated with progression of several other tumor types.