PTTG1 and esophageal squamous cell carcinoma: Overexpression of PTTG was reported in many cancers, such as lung, gastric, kidney, pancreatic, breast cholangiocarcinoma, psoriasis, adrenocortical carcinoma, hepatocellular carcinoma, glioblastoma, esophageal squamous cell carcinoma, and prostate cancer [7–15].