Prooxidant effect of α-tocopherol in pancreatic tumors.

Abstract

e16698 Background: The coexistence of neuroendocrine tumors and pancreatic adenocarcinoma is rare, and treatment of such mixed tumors is challenging due to the differences in their natural course and response to systemic therapy. There is growing evidence that vitamins affect the biology of pancreatic tumors. The purpose of the study was to measure concentrations of retinol (RET), α-tocopherol (α-TCP) and diene conjugates (DC) in the blood of patients with pancreatic cancer in order to reveal its pathogenetic characteristics. Methods: Blood levels of RET and α-TCP (ELISA methods, Cloud-Clone Corp, USA), their ratio and DC concentrations (biochemical method) were measured before treatment if 42 patients with pancreatic cancer: adenocarcinoma (AC), T1-3N0-1M0, n = 9; AC with a neuroendocrine component (AC+NE) (up to 30%), n = 21; neuroendocrine tumors (NET), T1-3N0-1M0, n = 12. 22 healthy men of similar age were controls. All patients gave their voluntary informed consent for the study. Results: RET levels in all patient were statistically significantly lower than in controls: in AC by 3.8 times, in AC+NE by 1.9 times, in NET by 3.7 times (p = 0.0000). Concentrations of α-TCP in AC were 1.6 times (p = 0.0011) lower than in controls, in AC+NE were similar, and in NET α-TCP was 1.5 times higher than in controls (p = 0.0000). The ratio of α-TCP/RET in all patients significantly exceeded control values: in AC by 2.2 times, in AC+NE by 1.6 times, in NET by 5.7 times (p = 0.0000). Levels of DC in all patients were higher than in controls: in AC by 2.5, in AC+NE by 2.1, in NET by 2.7 times (p = 0.0001). Conclusions: Changes in serum levels of RET and α-TCP differ in patients with AC, NET and mixed tumors, which causes changes in the balance of vitamins and can contribute to a prooxidant effect, as evidenced by an increase in DC levels.