Abstract:Objective: To investigate the correlation between the expression of T cell immunoglobulin mucin 3 (Tim-3) and chemoradiotherapy sensitivity of esophageal carcinoma (EC). Methods: Patients who admitted our hospital from January 2017 to December 2019 were diagnosed EC, and their pathological specimens and pathological data were collected. Immunohistochemistry was used to detect the expression of Tim-3 protein in EC tissues and adjacent tissues. Flow cytometry was used to detect the level of Tim-3 in peripheral blood. The relationship between the expression of Tim-3 protein and the pathological parameters of EC was analyzed. The Kaplan Meier survival curve was plotted to further evaluate the relationship between expression of Tim-3 protein and overall survival (OS) and disease-free survival (DFS). The relationship between the prognosis of EC and the expression of Tim-3 protein was analyzed by COX regression analysis. The ROC curve of Tim-3 on the prognosis of EC was plotted, and the area under the curve (AUC) was calculated. Results: After concurrent chemoradiotherapy, patients were divided into sensitive group (36 cases) and resistance group (42 cases). The expression of Tim-3 was high in EC tissues (85.90%), while it was slightly expressed in paracancerous tissues (10.26%). The difference was statistically significant (P<0.05). The abnormal expression of Tim-3 in EC was significantly different in depth of invasion, lymph node metastasis and TNM stage (P<0.05), and patients with high expression of Tim-3 had lower OS and DFS (P<0.05). COX regression analysis showed that high expression of Tim-3 (HR = 4.253, 95% CI 1.464-12.353) was an independent risk factor for chemoradiotherapy sensitivity in EC patients. The area under ROC curve was 0.848, the sensitivity and specificity of prediction were 86.2% and 76.3%, respectively. Conclusion: Tim-3 protein is highly expressed in cancer tissues and serum of EC patients resistant to radiotherapy and chemotherapy, which has a certain correlation with the sensitivity of EC to radiotherapy and chemotherapy, and can be used as a specific marker to predict EC.