SMAD7 and esophageal cancer: Among them, the expression levels of circ-DLG1 and circ-TTC17 were upregulated, yet hsa_circ_0001946, hsa_circ_0062459, and circ-SMAD7 were downregulated in the ESCC plasma, as the previous studies demonstrated that the expression levels of circ-DLG1 and circ-TTC17 were aberrantly increased in the ESCC tissue and esophageal cancer cells.