The expression of vascular endothelial growth factor and proliferative activity of cancer cells in gastric cancer

Vascular endothelial growth factor (VEGF) is one of the most important factors for angiogenesis in various malignant tumors. However, the clinicopathological and biological significance of the expression of VEGF in gastric cancer remains unclear. In this study, we investigated the relationship between the expression of VEGF and the clinicopathological and biological status of advanced gastric cancer, all of the same stage. The expression of VEGF was immunohistochemically examined using the polyclonal antibody A-20 in tumors from 97 patients with invasion of the serosa but no lymph-node metastasis (t3, n0, stage II). The results were compared with clinicopathological and biological status (microvessel density and proliferative activity) of tumors. Expression of VEGF was detected in 27 of 97 tumors (28%). The mean microvessel density (MVD) of 27 VEGF-positive tumors (458/mm2) was higher than that of 70 VEGF-negative tumors (331/mm2, P=0.0001). However, the proliferative activity expressed as the Ki-67 labeling index (LI; percentage of immunostained cancer cells) of 27 VEGF-positive tumors (13.8%) was significantly lower than that of 70 VEGF-negative tumors (26.7%, P=0.0002). In 48 tumors with low proliferative activity of cancer cells (Ki-67 LI < or =18%), 20 (42%) tumors expressed VEGF, and these tumors had a high MVD (4461/mm2). In the 93 surviving patients, the 5-year survival rate of the 25 patients with VEGF-positive tumors (64%) was not different from that of the 68 patients with VEGF-negative tumors (73%, P=0.4296). Advanced gastric carcinoma with low proliferative activity may produce VEGF and may have high angiogenic potential in order for the tumor itself to grow. However, the prognosis of patients with such tumors was not unfavorable.