Expression of the Cancer Stem Cell Markers CD44 and CD133 in Colorectal Cancer: An Immunohistochemical Staining Analysis

Purpose: The aim of this study was to assess the expressions of CD44 and CD133 in colorectal cancer tissue by using immunohistochemical staining and to analyze the clinical significance of the expressions related to other clinicopathological data and survival results. Methods: One hundred sixty-two patients with a biopsy-proven colorectal adenocarcinoma who were operated on between January 1998 and August 2004 were enrolled in this study. Immunohistochemical staining for CD44 and CD133 was performed on primary colorectal cancer tissue, metastatic lymph nodes, and synchronous and metachronous metastatic tumor tissues if available. Results: CD44 expression was stronger in the primary tumor than in metastatic lymph nodes (P < 0.001), and CD133 expression tended to be stronger in primary tumor than in metastatic lymph nodes (P = 0.057). No significant correlation was found between the CD44 and the CD133 expressions. The cases with recurrence showed low expression of CD44 (P = 0.017). CD133 expression was lower in cases with elevated CA 19-9 serum levels (P = 0.028) and advanced T stage (P = 0.038). Multivariate analysis proved that low expression of CD44 was an independent prognosis factor for short disease-free survival (P = 0.028). Conclusion: Low CD44 expression was correlated with increased tumor recurrence and short disease-free survival, and low CD133 expression was associated with advanced tumor stage. We suggest that further studies be performed to evaluate whether the immunohistochemical method for determining the CD44 and the CD133 expressions is appropriate for exploring cancer stem-cell biology in patients with colorectal cancer.