Correlation of thymidine phosphorylase staining and the Ki-67 labeling index to clinicopathologic factors and hepatic metastasis in patients with colorectal cancer.

Abstract

Our aim was to investigate the thymidine phosphorylase (TdRPase) expression and Ki-67 labeling index (LI) of primary tumors of colorectal cancer and hepatic metastases immunochemically and to evaluate the relationship of these parameters to various clinicopathologic factors and hepatic metastasis. We performed immunochemical studies in 74 patients with colorectal cancer, using anti-TdRPase antibody and MIB-1 antibody. TdRPase expression and a Ki-67 LI > or =30% in primary lesions were significantly more common in patients with lymphatic invasion (ly), venous invasion (v), lymph node involvement (n), and hepatic metastasis. A Ki-67 LI > or = 30% of the primary tumor was associated with a significantly higher frequency of metachronous liver metastasis. In the same patients, the mean Ki-67 LI was 24.3+/-17.9 for primary lesions and 5.0+/-4.2 for hepatic metastases, this difference being significant. These results indicate that TdRPase expression and the Ki-67 LI are related to various clinicopathologic factors, suggesting their usefulness as indices of tumor malignancy. We suggest that the Ki-67 LI of primary colorectal cancer could be an important predictor of the future development of metachronous liver metastasis.