Purpose: SK1, a human IgM monoclonal antibody recognizes the antigen, termed AgSK1 which was shown to be preferentially expressed by human adenocarcinomas, particularly human gastrointestinal malignancies. The aim of this study was to clarify the clinicopathological significance of AgSK1 mRNA expression in human colorectal cancer.
Methods: Using a quantitative RT-PCR, we studied the mRNA expression level of AgSK1 in the resected specimen of 40 patients with colorectal cancer. We estimated the tumor tissue value (T-value), nontumorous tissue value (N-value), and the ratio of T-value to N-value (T/N Ratio). For further analysis, we compared these data with the clinicopathological features.
Results: In the status of lymph node metastases, pN positive status tended to have a higher T-value level of AgSK1 mRNA than pN negative status (P = 0.076). According to a mean T-value (8.032) or a mean T/N Ratio (1.549), we divided these patients into two groups, low expression group and high expression group. A high expression group showed a significantly higher frequency of positive lymph node metastases (T-value; P = 0.021, T/N Ratio; P = 0.024).
Conclusion: AgSK1 mRNA expression in tumor tissue may become a useful marker for lymph node metastases and a malignant potential marker of colorectal cancer.