Expression of thymidine phosphorylase by macrophages in colorectal cancer tissues

Ji Min Zhang, Takayuki Mizoi, Ken Ichi Shiiba, Iwao Sasaki, Seiki Matsuno

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Aim: To detect the thymidine phosphorylase (dThdPase) expression in human colorectal cancer tissues and cells. Methods: Forty specimens resected from patients with colorectal cancer were immunohistochemically stained by 654-1, anti-dThdPase monoclonal antibody, PG-M1, anti-macrophage marker CD68 monoclonal antibody. Morphometrical analysis and positive cell counting were performed. In 27 of 40 specimens, dThdPase activity was also assayed by HPLC. Otherwise, the dThdPase level was measured by ELISA in 6 colorectal cancer cell lines, LS174T, Clone A, Colo320, CX-1, Lovo, and MIP101, as well as in 2 macrophage-like cell lines, THP-1 and U937. Results: dThdPase activity was significantly increased in cancer tissues compared with adjacent normal tissue (P<0.01). In immunohistochemical analysis, it was confirmed that most cells expressed dThdPase were the stromal cells surrounding cancer nests or along the invasive margin of cancer. Based on their morphometrical characteristics, we found that most of them were tumor-associated macrophages (TAMs). The number of dThdPase-positive stromal cells was significantly correlated with the number of CD68-positive macrophages (r=0.76, P<0.0001). By ELISA, 18.2 unit/mg and 19.3 unit/mg of dThdPase protein were detected in THP-1 and U937, but only little was detected in 6 colorectal cancer cell lines. Conclusion: The present data suggest that dThdPase expression is seldom detected in colorectal carcinoma cells. TAM is the most important source of dThdPase in colorectal cancer tissues.

Original languageEnglish
Pages (from-to)545-549
Number of pages5
JournalWorld Journal of Gastroenterology
Issue number4
Publication statusPublished - 2004 Feb 15
Externally publishedYes

ASJC Scopus subject areas

  • Gastroenterology


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