Overexpression of cyclooxygenase-2 in gastric cancer correlates with the high abundance of vascular endothelial growth factor-C and lymphatic metastasis

Cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF)-C are closely related with the development and metastasis of tumors. The gene expression of COX-2 and VEGF-C in gastric cancer and the correlation between them were investigated; 64 paraffin-embedded gastric cancer samples and 22 flesh gastric cancer samples were tested by using immunohistochemistry and the reverse transcription polymerase chain reaction (RT-PCR) technology, respectively. The mean expressive density of COX-2 and VEGF-C mRNA in gastric cancer, with P-actin coamplified as an internal standard, were both significantly higher than those in noncancerous gastric mucosa (1.363 +/- 0.351 vs 0.763 +/- 0.304, 0.972 +/- 0.331 vs 0.314 +/- 0.215, p < 0.001). The positive rates of COX-2 and VEGF-C in 64 gastric cancer samples were 72% and 64% respectively. Their expression in the lymph-node metastasis groups were higher than that of the non-lymph-node metastasis groups (p < 0.05). Moreover, there was a close correlation between COX-2 and VEGF-C expression levels (p < 0.05). The study indicates gastric tumor tissues that produce COX-2 and VEGF-C may have a higher lymphatic invasion and metastatic potential. COX-2 may participate in VEGF-C lymphangiogenic pathway and the high expression of them may play an important role in the lymphatic proliferation and spread in gastric cancer.