The roles of angiopoietins in gastric cancer progression are still not fully understood. In this study the expressions of angiopoietin-1 (Ang-1), -2 (Ang-2) were compared by immimohistochemistry in 53 gastric cancer and 23 normal gastric mucosa samples. Results revealed that Ang-2 expression was significantly increased in gastric cancer tissues (74%) and was correlated with higher TNM stage, lymph node metastasis as well as distance metastasis. The expression of Ang-1 was also elevated in cancerous tissues (66%) and significantly associated with differentiation degree. In addition, Ang-2 as well as its receptor Tie2 expressions were higher in 12 pairs of gastric cancer tissue samples than those in corresponding adjacent samples by Western blot, while Ang-1 expression showed great heterogeneity. Furthermore, the expressions of Ang-1 and Ang-2 were almost positive in eight gastric cancer cell lines. Among them, AGS expressed both Ang-2 and a relatively moderate amount of Ang-2(443), a novel splice form of Ang-2, while others showed only Ang-2 mRNA expression. (c) 2005 Elsevier Inc. All rights reserved.