Cytokeratin-Positive Cells in Lymph Nodes in Which Metastases Are Undetectable by Conventional Histological Staining in Advanced Gastric Cancer

Detection of occult metastases in lymph nodes by immunostaining is becoming of increasing interest as a way to improve the accuracy of predicting the prognosis for patients with gastric cancer. Immunohistochemical detection of cytokeratin (CK) is recognized as the most sensitive method for identification of cancerous epithelial cells. In this study, lymph nodes were stained for CK in an effort to detect micrometastases and the clinical implications of the results were examined. We immunostained sections from a total of 1,198 lymph nodes from 25 totally gastrectomized patients with T3 or T4 gastric cancer who had been diagnosed as having no nodal involvement by conventional hematoxylin-eosin (HE) staining. Eighty (6.7%) of 1,198 lymph nodes from 15 (60%) of the 25 patients were immunostained with a CK-specific monoclonal antibody. CK-positive cells were more frequent in patients with macroscopic types of 3,4 and 5 gastric cancer. Patients with nodes that were both HE-negative and CK-negative had the best postoperative survival, followed by patients with HE-negative and CK-positive nodes and, finally, by patiof micrometastases in lymph nodes is a reliable indicator of the prognosis of patients with advanced gastric cancer.