Prognostic impact of blood biomarkers TS and DPD in neoadjuvant-treated esophageal cancer patients

The prognostic value of TS (thymidylate synthase) and DPD (dihydropyrimidine dehydrogenase) RNA expression in the blood of patients with esophageal cancer is not known. The aim of the present study was to evaluate the significance of these molecular alterations in the blood as a prognostic marker for patients with neoadjuvant-treated esophageal cancer. A total of 29 patients with locally advanced esophageal cancer (cT3-T4, Nx, M0) were enrolled in this prospective study. All patients received neoadjuvant chemoradiation followed by a transthoracic resection (curative transthoracic en bloc esophagectomy, RO). Peripheral blood samples were drawn before initiation of therapy. The analysis was performed using quantitative real-time-polymerase chain reaction (RT-PCR). The histomorphological regressions grading after neoadjuvant therapy was defined as follows: major response (MaR)=less than 10% vital tumor tissue, minor response (MiR)=more than 10% vital tumor tissue. Nineteen out of 29 patients (65.5%) had a MiR and 10 (34.5%) had a MaR. The median survival of patients was 2.08 years (range=0.15-4.53). Among the tested genes, the RNA expression of TS was significantly associated with prognosis of patients. Patients with TS expression above 0.78 had a median survival of 1.1 years (range=0.21-3.96) compared to 2.6 years (range=0.15 to 4.53) in patients with TS expression lower than 0.78 (p=0.031, log rank test). There was no association between clinical variables (e.g., tumor stage, gender, age, etc.) and the RNA expression of TS in the serum. The RNA expression of TS in the blood is a potential prognostic marker in patients with neoadjuvant-treated esophageal cancer. The significance of these molecular alterations as non-invasive prognostic marker for esophageal cancer should be evaluated in prospective studies.