TUG1 and esophageal squamous cell carcinoma: LncRNA TUG1 was frequently upregulated and characterized as an oncogene involved in the development and progression of a variety of tumors (e.g., osteosarcoma [11], esophageal squamous cell carcinoma (ESCC) [12], urothelial carcinoma of the bladder [13], glioblastoma [14], colorectal cancer [15]).