Expression of thymidine phosphorylase in human metastatic liver cancer tissues from colorectal cancer

Abstract

Objective To detect the tbymidine pbospborylnse (TP) expression in metastatic liver cancer tissues from human colorectal cancer by immunohistochemistry, and analyze the correlation between TP ex-pression and the tumor-associated macrophages (TAM), and the prognosis of patients. Methods Twenty-eight metastatic liver cancer specimens resected from patients with colorectsl cancer, were immunohistochem-ically stained by 654-1, an anti-TP monoclonal antibody, IC6-203, another anti-TP monoclonal antibody, PG-M1, anti-macrophage marker CD68 monoclonal antibody. Morphometrical analysis and positive cell counting were performed, and the correlation of TP expression with the patient's prognosis was evaluated. Results In normal liver tissues, the hepatic cells apart from cancer nests were weakly positive for 654-1 as well as for 1C6-203. The most TP-positive cells were distributed mainly along the invasive margin of cancer or around the cancer nests. In the corresponding areas, CD68-positive macrophages were also increased. The distribution patterns of CD68-positive cells were similar to those of TP-pesitive cells. The numbers of the TP-positive cells stained by 654-1 were significantly correlated with numbers of 1C6-203 positive cells (r=0.697, P 0.05). The TP-pesitive cancer cells both for 654-1 and for 1C6-203 were detected only in 2 of 28 specimens. Both the number of TP-pesitive cells for 654-1 and 1C6-203, and the number of CD68-positive cells had no correlation with the survival period of patients. Conclusions In the metastatic liver cancer tissues of human colorectsl cancer, the TP-expreasinn stained by 654-1 was coincidence with 1C6-203, and the most important source of TP-expreasion is the TAM in stromal tissues around cancer nests, while the cancer cells are little expressed. The numbers of TP-positive cells stained by 654-1 are significantly related with CD68-pesitive macrophages, but not with the post-operation survival period of patients. Key words: thymidine phosphorylase; colorectal cancer; metastatic liver cancer; tumor-associated mac-rophages; prognosis