ECRG4 is also believed to be a TSG, as normal tissue levels of ECRG4 are high; whereas, it is down-regulated or silent in several types of tumor such as human esophageal squamous cell carcinoma, nasopharyngeal carcinoma, renal cell cancer, colorectal carcinoma, gastric cancer, and hepatocellular carcinoma [4–10]. Here, ECRG4 is linked to esophageal squamous cell carcinoma.