Relationship between the proportion of regulatory T cells in peripheral blood and the immune condition and prognosis in patients with gastric cancer

Objective To investigate the relationship between the proportion of regulatory T (Treg) cells in the peripheral blood and the clinicopathological characteristics, PDL1 and HER2 expression, and survival and prognosis in patients with gastric cancer. Methods A total of 85 patients with gastric cancer and 85 healthy subjects in the First People's Hospital of Xuzhou were enrolled and the proportions of Treg cells in peripheral blood were collected. The proportions of Treg cells in peripheral blood and the levels of cytokines IL-6, IL-17 and IL-1β in gastric cancer patients and healthy subjects were analyzed. The relationship between Treg cell proportion and PDL1 and HER2 expression in peripheral blood was evaluated. Survival analysis and Cox regression model were used to investigate the relationship between the proportion of Treg cells in peripheral blood and survival and prognosis of gastric cancer patients. Results The proportion of Treg cells was (15.3±3.6)% for healthy subjects, and (43.4±9.3)% in gastric cancer patients, which were statistically different (P<0.01). For healthy subjects, their level of IL-6 was (3.23±1.06) ng/L, IL-17 was (1.45±0.36) ng/L, and IL-1β was (4.6± 1.2) ng/L. Meanwhile, for gastric cancer patients, their level of IL-6 was (8.41±2.14) ng/L, IL-17 was (4.31±1.12) ng/L and IL-1β was (9.3±3.4) ng/L before surgery, which were statistical different from those in healthy subjects (P<0.01). For gastric cancer patients, high Treg cell proportion in peripheral blood was not related with gender (P=0.939), age (P=0.915), T stage (P=0.144), PDL1 expression (P=0.588), and HER2 expression (P=0.381), but was related with N stage (P<0.001) and clinical stage (P<0.001). According to Cox regression multivariate model analysis, except for N stage (HR=2.299, P=0.015), Treg cell proportion in peripheral blood (HR=4.266, P<0.001) was an independent prognostic factor for gastric cancer patients. Conclusions Detection of Treg cell proportion in peripheral blood before surgery can preliminarily determine the prognosis and immune condition of gastric cancer patients.