The effect of MKN45 on the angiogenesis of HUVEC in COX-2-positive gastric cancer cells was significantly stronger than that in COX-2-negative gastric cancer cells (NUGC-4); ω-6 PUFAs could promote the angiogenesis of COX-2-positive gastric cancer cells, while ω-3 PUFAs could inhibit the angiogenesis of COX-1-positive gastric cancer cells. This evidence concerns the gene PTGS2 and gastric cancer.