Relationships between S-100 protein-positive cells and clinicopathological factors in patients with colorectal cancer.

Background: An increased number of dendritic cells (DCs), as indicated by positive S-100 protein staining, has been shown to correlate with good prognosis in several malignancies. The clinicopathological significance of S-100 protein-positive cells in human colorectal cancer is unclear and was thus examined. Patients and Methods: We investigated the relationships between the density of S-100 protein-positive cells at the peripheral area of the tumor, prognosis and clinicopathological factors in 30 patients with colorectal cancer. S-100 protein-positive cells were detected by immunohistochemistry using a mouse monoclonal antibody against S-100 protein. Results: The number of S-100 protein-positive cells was significantly higher in patients with a good prognosis or those without recurrence or worsening of their condition, but was significantly lower in patients with lymph node metastasis, T3-T4, hepatic metastasis or tumors more advanced than stage III (TNM). Conclusion: S-100 protein-positive cells may act as one line of defense against malignant cells in patients with colorectal cancer.