Abstract: Objective:To explore the correlation between the baseline expression of inducible costimulatory factor(ICOS) and the prognosis of patients with esophageal cancer after surgery.Methods:A total of 139 patients with esophageal cancer diagnosed and treated from June 2016 to April 2018 in Zouping People's Hospital were included as the research subjects.After admission,the clinical data and ICOS expression levels of the patients were collected,and the median ICOS expression level was used as the cutoff value.Divided into ICOS low expression group(n=60) and ICOS high expression group(n=60).All subjects underwent esophageal cancer resection.After 2 years of followup,the two groups of patients after esophageal cancer resection were compared with the twoyear risk of poor prognosis.According to the prognosis of all subjects,they were divided into a poor prognosis group and a good prognosis group.To analyze the risk of poor prognosis of patients after esophageal cancer resection and the influencing factors that affect the shortterm prognosis of patients with esophageal cancer resection,draw a working characteristic curve(ROC) to analyze the predictive power of baseline ICOS expression level.Results:As of the last followup time on April 27,2020,139 patients,120 patients in total,completed the followup,and 120 patients were finally enrolled.Among them,a total of 55 patients with a poor prognosis were classified as the poor prognosis group,and 65 patients without a poor prognosis were regarded as the prognosis Good group.KM survival analysis curve showed that the twoyear risk of poor prognosis in patients with high ICOS expression group after esophageal cancer resection was lower than that in ICOS low expression group(P<0.05);multivariate Logistics multivariate showed lymph node metastasis(OR=0.132) and degree of differentiation(OR=0.359) Baseline ICOS low expression(OR=0.303) is a risk factor for poor prognosis of patients after esophageal cancer resection;ROC curve analysis shows that baseline ICOS low expression predicts the AUC of poor prognosis risk for patients after esophageal cancer resection Is 0.726.Conclusion:Lymph node metastasis,degree of differentiation,and low baseline ICOS expression are risk factors for poor prognosis of patients after esophageal cancer resection.Low ICOS expression can be used as an important indicator for predicting the risk of poor prognosis for patients after esophageal cancer resection.