First, by TCGA database CST1 expression was shown significantly upregulated in esophageal cancer tissues, and closely correlated with grades, stages, lymph node metastasis and survival probability; And then, by immunohistochemistry staining, CST1 protein was shown aberrantly expressed in ESCC tissues with the positive rate up to 68.1% (32/47) in cancerous tissues significantly higher than 0% (0/47) in paracancerous tissues (P<0.01), and closely correlated with tumor stages. The gene discussed is CST1; the disease is esophageal squamous cell carcinoma.