SNAI2 and head and neck squamous cell carcinoma: Additionally, the negative correlation between Slug and EpCAM expression in bladder urothelial carcinoma (BLCA), colon adenocarcinoma (COAD), esophageal carcinoma (ESCA), breast invasive carcinoma (BRCA), head and neck squamous cell carcinoma (HNSC), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), prostate adenocarcinoma (PRAD) and stomach adenocarcinoma (STAD) was confirmed from the GEPIA online database (Additional file 1: Figure S3A).