Immunohistochemical expression of thymidylate synthase as a prognostic factor and as a chemotherapeutic efficacy index in patients with colorectal carcinoma

Background: We assessed the importance of Thymidylate Synthase (TS) express ion as a prognostic factor and as an index of therapeutic efficacy in patie nts with colorectal carcinoma. patients and Methods: TS expression in 66 pa tients with colorectal carcinoma was immunohistochemically assessed using t he anti-TS antibody. TS expression, TS activity clinicopathological charact eristics and survival were evaluated and the correlation among them was stu died Results: The cases studied included 53 patients with low grade positiv e/negative and 13 patients with high grade positive TS expression. TS level s were 8.69+/-10.01pmol/g and 14.82+/-11.38 pmol/g, respectively. There was not correlation between clinicopathological characteristics and TS express ion. Considering TS expression, the 5-year survival rate was significantly better for the 75.5% of the patients with low grade positive/negative TS th an for the 38.5% of the patients with high grade positive TS (p<0.01). Conc lusion: The immunohistochemical expression of TS should be further investig ated as a prognostic factor of survival and as an index of chemotherapeutic efficacy in colorectal carcinoma.