Clinical significance of subcellular localization of KL-6 mucin in primary colorectal adenocarcinoma and metastatic tissues

Abstract

Aim: To assess subcellular localization of KL-6 mucin and its clinicopathological significance in colorectal carcinoma as well as metastatic lymph node and liver tissues. Methods: Colorectal carcinoma tissues as well as metastatic lymph node and liver tissues were collected from 82 patients who underwent colorectomy or hepatectomy. Tissues were subjected to immunohistochemical analysis using KL-6 antibody. Results: Of the 82 colorectal carcinoma patients, 6 showed no staining, 29 showed positive staining only in the apical membrane, and 47 showed positive staining in the circumferential membrane and/or cytoplasm. Positive staining was not observed in non-cancerous colorectal epithelial cells surrounding the tumor tissues. The five-year survival rate was significantly lower in cases showing positive staining in the circumferential membrane and/or cytoplasm (63.0%) than those showing positive staining only in the apical membrane (85.7%) and those showing no staining (100%). Statistical analysis between clinicopathological factors and subcellular localization of KL-6 mucin showed that KL-6 localization in the circumferential membrane and/or cytoplasm was significantly associated with the presence of venous invasion (P = 0.0003), lymphatic invasion (P < 0.0001), lymph node metastasis (P < 0.0001), liver metastasis (P = 0.058), and advanced histological stage (P < 0.0001). Positive staining was observed in all metastatic lesions tested as well as in the primary colorectal carcinoma tissues. Conclusion: The subcellular staining pattern of KL-6 in colorectal adenocarcinoma may be an important indicator for unfavorable behaviors such as lymph node and liver metastasis, as well as for the prognosis of patients. © 2006 The WJG Press. All rights reserved.