Elevated levels of mRNAs encoding dihydropyrimidine dehydrogenase and thymidylate synthase are associated with improved survival of patients with hepatocellular carcinoma treated with S-1.

Thymidylate synthase (TYMS) and dihydropyrimidine dehydrogenase (DPYD) are associated with the response of tumors to fluoropyrimidines. The aim of the present study was to investigate the association between the levels of TYMS and DPYD mRNAs and the efficacy of S-1 for treating patients with HCC. A total of 35 patients with HCC who received S-1 upon recurrence (S-1 group) and 20 patients who never received a fluoropyrimidine (control group) were studied. The levels of TYMS and DPYD mRNA in surgically resected specimens were determined using reverse transcription-polymerase chain reaction assays. Overall survival (OS) time of S-1 group patients with high levels of DPYD mRNA was significantly longer compared with that of patients with low levels (median 501 days vs. 225 days; P=0.016). Similarly, the OS time of those patients with high levels of TYMS mRNA was significantly longer compared with those with low levels (median 503 days vs. 239 days; P=0.0076). By contrast, there was no difference in OS time of the control group between patients with high and low levels of DPYD and TYMS mRNAs. The levels of TYMS and DPYD mRNAs may serve as predictive markers for patients with HCC who receive S-1 chemotherapy.