Acceleration of the proliferative activity of esophageal carcinoma with invasion beyond the muscularis mucosae; immunohistochemical analysis using MIB-1 for the Ki-67 antigen

Squamous cell carcinoma of the esophagus with cancer invasion beyond the muscularis mucosae is known to have lymph node metastasis and lymphatic or blood vessel invasion compared with intramucosal carcinoma. In submucosal and T2-3 carcinoma, lymph node and lymphatic/vascular involvement are shown more frequently, leading to a poor prognosis. Therefore, we examined proliferative activity of esophageal squamous cell carcinoma including early carcinoma in relation to clinicopathological findings. 77 cases of esophageal squamous cell carcinoma, including 23 cases of mucosal carcinoma (Tis+T1a), 35 cases of submucosal carcinoma (T1b) and 19 cases of advanced invasive carcinoma (T2+T3) undergoing surgical resection without preoperative treatment were studied using monoclonal antibody MIB-1 for Ki-67 antigen immunohistochemically, and the labeling index (LI) was calculated. The LI of MIB-1 positive nuclei correlated with the depth of cancer invasion was significantly increased in the cancer invading beyond the musculais mucosae. The LI at the invasive tip was significantly higher than that at the core of differentiated carcinoma. The LI values at both invasive tip and core of poorly differentiated carcinoma were higher than those of differentiated carcinoma with significant difference. The LI at the invasive tip of the carcinoma with lymph node metastasis or lymphatic invasion was significantly higher than that without them. Proliferative activities of esophageal cancer cell, immunostaining with MIB-1, had correlations to depth of tumor invasion, differentiation, lymph node metastasis and lymphatic invasion with significant difference. But if invading deeper than m3, the proliferative activity did not increase anymore.