Clinical significance of altering epithelial–mesenchymal transition in metastatic lymph nodes of gastric cancer

Background: The E-cadherin, N-cadherin, and Snail genes are epithelial–mesenchymal transition (EMT)-inducible genes. Previous studies demonstrated that the expression of EMT markers in the primary tumor sites of gastric cancer correlates with tumor progression and prognosis. However, the clinical significance of the expression of these EMT markers in metastatic lymph nodes remains unclear. In the present study, we investigated the expression of these EMT markers in the primary tumor sites and metastatic lymph nodes. Methods: Immunohistochemistry was used to investigate the expression of E-cadherin, N-cadherin, and Snail in 89 primary tumors and 511 metastatic lymph nodes obtained from patients with gastric cancer. Results: The weak expression of E-cadherin in tumors and lymph nodes increased with more lymph node metastasis and in more undifferentiated tumors. The strong expression of N-cadherin in lymph nodes correlated with more lymph nodes metastasis, an advanced stage, and poor prognosis. The weak expression of Snail in tumors correlated with lymphatic invasion. The strong expression of Snail in lymph nodes correlated with more lymph node metastasis and an advanced stage. The strong expression of Snail in tumors and its weak expression in lymph nodes correlated with more lymph node metastasis, an advanced stage, and poor prognosis. Conclusions: The expression of N-cadherin in metastatic lymph nodes is useful for predicting the prognosis of patients with gastric cancer. The Snail switch—namely, the positive-to-negative conversion of the Snail status—between primary tumors and lymph node metastasis may be important for confirming EMT and mesenchymal–epithelial transition.