RESUMEN
BACKGROUND & OBJECTIVE: Lymph node micrometastasis in early gastric cancer is being widely discussed. Cytokeratin (CK) staining is an important way to distinguish epithelial cancer cells. This study was to investigate the correlations of epithelial cadherin (E-cad) expression to lymph node micrometastasis, and clinicopathologic features of early gastric cancer, and to evaluate its clinical significance. METHODS: Morphology of 4522 lymph nodes from 162 patients with early gastric cancer was observed with HE staining and CK immunostaining. E-cad expression in 135 primary lesions of these patients was detected by immunohistochemistry. The correlations of E-cad expression to clinicopathologic features were analyzed. RESULTS: The detection rate of lymph node metastasis by CK staining was significantly higher than that by HE staining (26.5% vs. 6.8%, P<0.001). CK immunostaining detected 32 cases of lymph node micrometastasis which were missed by HE staining. Lymph node micrometastasis was frequently found in primary tumors with a diameter of more than 1.0 cm, in those that were poorly differentiated, deeply invaded (for example, to the submucosa), showed lymphatic or vascular invasion, and in those that showed loss of E-cad expression (P<0.05). The reduced expression rate of E-cad in primary tumor was 57.0%, closely correlated to lymph node micrometastasis. The 5-year survival rate was significantly lower in the patients with lymph node micrometastasis than in those without such metastasis (93.6% vs. 100%, P<0.01). CONCLUSION: Primary tumor more than 1.0 cm in diameter, poor differentiation, deep invasion, lymphatic or vascular invasion, and loss of E-cad expression are risk factors for lymph node metastasis in early gastric cancer.