Correlation between serum vascular endothelial growth factor (VEGF) and VEGF-1 expression in patients with colorectal cancer. Preliminary results.

Background: In patients with colorectal cancer (CRC), several growth factors have been identified as regulator of angiogenesis, including vascular endothelial growth factor (VEGF), a pro-angiogenetic factor which can be safely measured in the blood. Angiogenesis plays an important role in the progression of CRC, as well as in the development of regional lymph node and distant metastases. VEGF is minimally expressed or not expressed in colorectal adenomas and in normal colonic mucosa, while it is overexpressed in inflammatory bowel diseases as well as in CRCs. It has been shown that high microvessels density, an indirect measure of the degree of angiogenesis, correlates with increased tumor aggressiveness and risk of metastasis development, and that overexpression of VEGF in cancer tissues represents a sensitive marker of angiogenesis. Because undetected metastases can contribute to the failure of primary treatment, their early identification has a substantial impact on adequate therapy. In this setting, several serum tumor markers and tissue-extracting prognostic factors have been tested, including angiogenic cytokines such as VEGF. In several studies, preoperative serum VEGF was increased in patients with CRC compared to controls, and high VEGF serum concentration tended to occur with more advanced disease. However, these data are not confirmed, and VEGF overexpression in cancer tissues significantly correlates with tumor biology. The aim of this study was to evaluate the relationship between serum VEGF, and the expression of VEGF-1 in patients with CRC. Methods: Archival paraffin-embedded tumor samples from 38 patients (26 men, 12 women, median age 64, range 39-76 years) with stage I-II colorectal adenocarcinoma who underwent intentionally curative surgical resection, were reviewed. None of the patients received preoperative adjuvant chemotherapy. Written informed consent was obtained from all the participants. Serum VEGF was measured with a commercially available human VEGF quantitative enzyme-linked immunosorbent assay (ELISA) kit, according to the manufacturer’s instructions. All analyses were made in duplicate, and the mean value was used for statistical calculation. Tissue microarray blocks for immunohistochemistry staining was obtained, serial 4 μm sections were cut, and then assessed using a commercial anti-human VEGF (clone VG-1). The Pearson’s correlation coefficient calculation was used to evaluate results. Results: The expression of VEGF was tested using a 4-grade scoring system, according to the degree of cytoplasmic staining, ranging from negative to intense staining. Overall, the mean serum VEGF concentration was 272.7±140.5 pg/mL (range 41-670 pg/mL), while the VEGF-1 grade was 2.8±1.0. There was a significant relationship between the stage of the disease and VEGF (R=0.43, p=0.006), and between serum VEGF and VEGF-1 grade (R=0.64, t=5.06, p<0.001). The age did not correlate with VEGF (R=0.13, p=0.44) and VEGF-1 (R=-0.21, p=0.19). Conclusions: Tumor growth is dependent on the degree of angiogenesis, and VEGF is potent growth factor with angiogenic activity. It can safely be tested by measurements of both serum VEGF levels and grade of tumor tissue expression of VEGF-1. References: Bendaraf A et al. Anticancer Res 2008; 28: 3865-3870; Werther K et al. BJC 2002: 86: 417-423.