Clinical application of the biomarkers for the selection of adjuvant chemotherapy in pancreatic ductal adenocarcinoma.

Background: For the establishment of personalized therapy, we investigated biomarkers that can contribute to the selection of adjuvant therapy for pancreatic ductal adenocarcinoma (PDAC).

Methods: Between 2005 and 2014, of 141 consecutive patients with PDAC who underwent R0 or R1 resection, 61 patients given gemcitabine and 31 patients given S-1 as adjuvant therapy were enrolled. We evaluated the correlation between treatment outcomes and the expressions of intratumoral human antigen R (HuR), human equilibrative nucleoside transporter 1 (hENT1), thymidylate synthetase (TS) and dihydropyrimidine dehydrogenase (DPD).

Results: There were no significant differences in clinicopathological features between the gemcitabine and S-1 groups. Among those with high HuR expression and high hENT1 expression, the disease-free survival (DFS) was significantly higher with gemcitabine than with S-1 (MST: 26.2 vs. 11.8 months, P = 0.024; 20.2 vs. 10.2 months, P = 0.029, respectively). Moreover, high HuR/hENT1 (high HuR or high hENT1) was significantly associated with better outcome for gemcitabine (HR for DFS: 0.43, P = 0.027) and low HuR/hENT1 was significantly associated with worse outcome for gemcitabine (HR for DFS: 2.24, P = 0.021). TS and DPD expression levels were not informative in this examination.

Conclusions: HuR and hENT1 were good candidates as selective biomarkers and this study's concept could contribute to personalized therapy for PDAC patients.