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

ABSTRACT

BACKGROUND: We assessed the importance of Thymidylate Synthase (TS) expression as a prognostic factor and as an index of therapeutic efficacy in patients with colorectal carcinoma. PATIENTS AND METHODS: TS expression in 66 patients with colorectal carcinoma was immunohistochemically assessed using the anti-TS antibody. TS expression, TS activity, clinicopathological characteristics and survival were evaluated and the correlation among them was studied. RESULTS: The cases studied included 53 patients with low grade positive/negative and 13 patients with high grade positive TS expression. TS levels were 8.69 +/- 10.01 pmol/g and 14.82 +/- 11.38 pmol/g, respectively. There was not correlation between clinicopathological characteristics and TS expression. Considering TS expression, the 5-year survival rate was significantly better for the 75.5% of the patients with low grade positive/negative TS than for the 38.5% of the patients with high grade positive TS (p < 0.01). CONCLUSION: The immunohistochemical expression of TS should be further investigated as a prognostic factor of survival and as an index of chemotherapeutic efficacy in colorectal carcinoma.