Abstract: Objective The aim of this study was to evaluate the expression of programmed cell death 1(PD-1),cytotoxic T lymphocyte associated antigen-4(CTLA-4)and B and T lymphocyte attenuator(BTLA)in the peripheral blood of patients with esophageal squamous cell carcinoma(ESCC)and their clinical significance was analyzed. Methods A total of 90 patients with esophageal squamous cell carcinoma and 40 healthy controls at the department of Thoracic Surgery of the Fourth Hospital of Hebei Medical University were enrolled and collected their peripherals from June 2016 to April 2017.Blood samples from 50 patients underwent surgery from 90 patients and 40 healthy controls were assayed by enzyme-linked immunosorbent assay for soluble PD-1(sPD-1),soluble CTLA-4(sCTLA-4)and soluble BTLA(sBTLA). Results The serum levels of sPD-1,sCTLA-4 and sBLTA in the esophageal squamous cell carcinoma group were significantly higher than those in the normal control group(P＜0.05);the serum levels of sPD-1,sCTLA-4andsBLTA had no differences between before and after surgery(P＞0.05).There was no correlation between the level of sPD-1 and sBLTA and clinicopathological features.The expression level of CTLA-4 was related to the TNM stage(P＜0.05),but there were no correlation with T stage,lymph node status,tumor size,tumor location,tumor cell differentiation,sex and age.There was also no correlation amongst sPD-1,sCTLA-4 and sBLTA expression. Conclusion The serum level of sCTLA-4 in patients with esophageal squamous cell carcinoma is higher than that in normal individuals,and the expression level of sCTLA-4 is correlated with the TNM stage,suggesting that the expression level of sCTLA-4 in serum has a certain correlation with the development of esophageal squamous cell carcinoma.

Key words: Esophageal squamous cell carcinoma, Programmed cell death 1, Cytotoxic T lymphocyte associated antigen-4, Band T lymphocyte attenuator