ZEB1 and oral cavity carcinoma: An increasing number of studies have shown that over-expression of ZEB-1 was related to shorter survival in several types of human solid tumors, including colorectal cancer, [10–12] gastric cancer, [13, 14] hepatocellular carcinoma, [15, 16] pancreatic cancer, [17, 18] esophageal squamous cell carcinoma, [19, 20] oral cavity carcinoma, [21] and intrahepatic cholangiocarcinoma.