PURPOSE: Angiogenesis is required for tumor growth and metastasi. Vascular endothelial growth factor (VEGF) is one of the most important angiogenic cytokines. VEGF was expressed by several human solid tumors and serum VEGF levels have previously been shown to be raised in patients with breast, gastrointestinal tract, renal, ovarian cancer and melanoma. Tumor-derived VEGF plays a pivotal role in malignant ascites formation likely by increasing vascular permeability. In present study, amount of VEGF in plasmas and tumor tissues and cytology-proven malignant ascites were tested and compared with their normal counterparts and tumor stage to know relationship between the disease progression and VEGF quantitation in patients with stomach cancer. Also change of plasma VEGF level after tumor resection was performed. MATERIALS AND METHODS: VEGF level was measured by ELISA in plasmas from 81 patients and tumors and peritumoral mucosas (5 cm from the tumor) from 43 patients and malignant ascites from 14 patients with gastric carcinoma. Also level of plasma VEGF from 48 patients was measured after tumor resection. RESULTS: VEGF levels were significantly higher in plasma and in tumor tissues than in normal controls and in peritumoral mucosas. The levels of VEGF in plasma and tumor tissue were significantly correlated with the stage of disease. Moreover Tl showed significantly elevation of plasma VEGF level than those of controls. A significant correlation was found between plasma VEGF and tumor VEGF levels in stomach cancer patients. VEGF levels in fluid of cytology- proven malignant ascites were higher than in ascitic fluid with benign diseases. Plasma VEGF level fell after tumor resection, CONCLUSION: VEGF could act in a supporting tumor progression and may be useful for predicting prognosis of patients with gastric carcinoma.