CST1 and esophageal squamous cell carcinoma: By immunohistochemical staining of 47 pairs of ESCC tissues and paracancerous tissues, CST1 protein was shown aberrant expression evidented by the positive rate up to 68.1% in cancerous tissues significantly higher than that of paired paracancerous tissues (Table 1, Fig 2A and 2B), and correlated with tumor stages; in addition, by RT-qPCR of 20 pairs of ESCC tissues and paracancerous tissues, CST1 mRNA levels in ESCC tissues were also shown significantly upregulated (Fig 2C).