PTTG1 and esophageal squamous cell carcinoma: We used seven data sets, including six GeneChips (GPL570, GPL571, GSE23400, GSE32424, GSE45168, and GSE70409), and RNA-seq data (2,307 cases in total, with 620 cases of ESCC and 1,687 non-cancer cases) to investigate the expression of PTTG1 in ESCC.