Clinical Evaluation of Thymidine Phosphorylase Activity in Human Gastric Cancer with Special Reference to Metastatic Lymph Nodes and Relapsing Forms

Hiroshi Yabusaki, Atsushi Nashimoto, Yoshiaki Tsuchiya, Mitsuhiro Tsutsui,
Otsuo Tanaka and Juei Sasaki

Division of Surgery, Niigata Cancer Center Hospital

To investigate the expression of thymidine phosphorylase/platelet-derived endothelial cell growth factor (dThdPase/PD-ECGF) in gastric cancer, we measured its activity in normal tissues, cancer tissues and metastatic lymph nodes of 75 patients with resected advanced gastric cancer, and compared the results with histopathological features. We also evaluated cancer tissues immunohistochemically using anti-dThdPase antibody. The dThdPase activity was significantly higher in metastatic lymph nodes than in normal tissues (p<0.0001) and in cancer tissues (p=0.0002). There exists a definite correlation between cancer tissues and metastatic lymph nodes. Furthermore, dThdPase activity in cancer tissues was significantly higher in expansive type in growth pattern (p=0.0176), medullary type in stroma (p=0.0057), they are thought to have a close relationship with hematogenous metastasis, and INFα type in mode of infiltrative growth (p=0.0289), and also significantly lower in negative of lymph node metastasis (p=0.0383). Immunohistochemical study clarified that dThdPase activity of cancer tissue was significantly higher in the positive staining group than in the negative staining group of expansive type. Relapsed cases of peritoneal dissemination had significantly lower dThdPase activity in cancer tissue compared to non relapsed cases and other relapsing forms. In conclusion, dThdPase expression in advanced gastric cancer is higher in metastatic lymph nodes, and the relation between its expression in cancer tissues and hematogenous metastasis is speculated. Also, dThdPase expression has negative correlation with lymph nodes metastasis and a relapsed form of peritoneal disemination. Immunohistochemical study of expansive type is considered to be a very useful method.

Key words
thymidine phosphorylase, gastric cancer, lymph node metastasis of gastric cancer, relapsing forms of gastric cancer, immunohistochemical study

Reprint requests
Hiroshi Yabusaki Division of Surgery, Niigata Cancer Center Hopsital 2-15-3 Kawagishicho, Niigata, 951-8566 JAPAN

Accepted
May 25, 1999

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