Evaluation of effects of thymidylate synthase and excision repair cross-complementing 1 polymorphisms on chemotherapy outcome in patients with gastrointestinal tumors using peripheral venous blood

The aim of the present study was to evaluate the effects of thymidylate synthase (TYMS) and excision repair cross-complementing 1 (ERCC1) polymorphisms on chemotherapeutic efficacy in patients with gastrointestinal tumors using peripheral venous blood. Preoperative peripheral venous blood and tumor tissue samples of 43 patients with gastric cancer and the peripheral venous blood samples of 76 patients with cancer who underwent chemotherapy were studied. The 3R/3R and 2R/2R or 2R/3R genotypes of TYMS were identified in 72.09 and 27.91%, respectively (P<0.01), of untreated patients, and the C/C and T/T or C/T genotypes of ERCC1 were present in 81.39 and 18.61%, respectively (P<0.01), of patients. The 3R/3R and 2R/2R or 2R/3R genotypes of TYMS were identified in 65.79 and 34.21%, respectively, of chemotherapy-treated patients. The overall response rates (ORRs) for the two aforementioned genotypes were 18.00 and 57.69%, respectively (P<0.01), and those for the C/C and T/T or C/T genotypes of ERCC1 were 63.16 and 36.84%, respectively. The ORRs were 47.91 and 3.57%, respectively (P<0.01). In conclusion, peripheral blood samples may be used to replace tumor tissue for detecting TYMS and ERCC1 polymorphisms, and may be used to evaluate the efficacy of 5-fluorouracil and platinum drugs.