TUG1 and esophageal squamous cell carcinoma: Recent studies reported TUG1 was up-regulated in colorectal cancer resistant to methotrexate, knockdown of TUG1 re-sensitized the colorectal cancer cells to methotrexate [21]; high TUG1 expression was related to chemoresistance in esophageal squamous cell carcinoma to platinum combined with 5-fluorouracil or paclitaxel [22].