Expression of metabolic enzymes of fluoropyrimidines in primary colorectal cancer and its clinical significance

To investigate the expression of metabolic enzymes of fluoropyrimidines in primary colorectal cancer.Sixty-one cases of pathological confirmed primary colorectal cancer were collected in Beijing Cancer Hospital from August 2003 to February 2004. The expressions of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and orotate phosphoribosyl transferase (OPRT) were detected in paired tumor tissues and non-cancerous tissues by RT-PCR.Expression of each enzyme in tumor tissues was positively correlated with that in paired non-cancerous tissues respectively. Compared with the expression of each enzyme in cancer with that in non-cancer, OPRT was higher in cancer while that of DPD and TS was comparable. The expression of OPRT was approximately 4.38-folds higher in colorectal cancer tissues than that in non-cancerous tissues (P=0.000). The lowest expression of OPRT was found in mucinous carcinoma while the highest levels in poorly-differentiated adenocarcinoma. There were correlations between the ratio of tumor tissues/non-cancerous tissues OPRT expression (T/N) and metastasis to the lymph nodes (r=0.36; P=0.005), small vessel invasion (r=0.26; P=0.041) and differentiation (r=-0.33; P=0.009).The detection of three enzymes by means of RT-PCR is practical and can be used in clinical application. Our results also suggest that OPRT is a potential biomarker in predicting prognosis of colorectal cancer.PubMed03269-723