Objective:To explore the clinical significance of the expression of nuclear factor of activated T cells 5 (NFAT5) in esophageal cancer tissues and the effect of the expression of knock-down esophageal cancer cells on their migration ability.Methods:The expression of NFAT5 in tissues of 26 patients with esophageal cancer and their adjacent tissues was detected by immunohistochemistry. Esophageal cancer cells ECA109 were divided into experimental group and control group. The experimental group ECA109 cells were transfected with NFAT5-siRNA plasmid, and the control group ECA109 cells were transfected with MOCK-siRNA plasmid. The mRNA content of NFAT5 was detected by fluorescence quantitative PCR. The expression of NFAT5, TLR4 and MyD88 proteins in the experimental group and control group were detected by Western blot. Transwell assay and cell scratch assay were used to detect the migration ability of the experimental group and the NC group.Results:Immunohistochemical test results showed that the positive rate of NFAT5 in esophageal cancer tissues was 80.77% (21 cases/26 cases) , and the expression rate was 15.38% (4 cases/26 cases) in corresponding adjacent tissues. The positive rate of NFAT5 protein in esophageal cancer tissues was significantly higher than that in adjacent tissues ( P<0.001) . The NFAT5 mRNA content of ECA109 cells in experimental group and control group decreased after transfection with corresponding siRNA. The protein expression levels of NFAT5, TLR4 and MyD88 in ECA109 cells in the experimental group were 0.28±0.08, 0.31±0.13 and 0.41±0.14, respectively. The protein expression levels of NFAT5, TLR4 and MyD88 in ECA109 cells in control group were 0.95±0.15, 0.84±0.22 and 1.04±0.26, respectively. The expression of TLR4 and MyD88 in esophageal cancer ECA109 cells decreased significantly ( P<0.05) . The scratch healing rate of esophageal cancer ECA109 cells was 52.67%±5.21% in the experimental group and 82.91%±7.26 % in the control group. Transwell experiment results showed that the number of successfully migrated cells in the experimental group was (35±5) , and the number of successfully migrated cells in the control group was (92±13) . The results showed that the migration ability of esophageal cancer ECA109 cells was significantly decreased after low expression of NFAT5 ( P<0.01) . Conclusions:The expression of NFAT5 is significantly increased in esophageal cancer tissues, and the expression of NFAT5 may be related to the malignant degree of esophageal cancer. Moreover, NFAT5 affects the migration ability of esophageal cancer cells by regulating TLR4/MyD88 signaling pathway.