Correlation between thymidylate synthase and chemosensitivity to pemetrexed and raltitrexed in gastric cancer

Objective To investigate the correlation between the thymidylate synthase(TS) mRNA expression levels and in vitro chemosensitivity of gastric tumor specimens to pemetrexed and raltitrexed.Methods Freshly-removed gastric tumor specimens were collected from 50 patients.Chemosensitivities to pemetrexed and raltitrexed were evaluated by histoculture drug response assay(DHRA);quantitative RT-PCR(qRT-PCR) was adopted for TS mRNA detection.Results There was no significant association between clinical characteristics and in vitro chemosensitivity or TS mRNA levels.TS mRNA levels in pemetrexed-sensitive group and raltitrexed-sensitive group were significantly lower than resistant groups(pemetrexed: 6.72 ± 1.34 vs.15.39 ± 2.43,P=0.002;raltitrexed: 7.96 ± 1.70 vs.14.14 ± 2.37,P=0.028).Conclusion TS mRNA expression level in gastric cancer is negatively correlated with in vitro chemosensitivity to pemetrexed and raltitrexed in gastric cancer.TS has potential predicting value in individual therapy of new antifolic acid drugs.