Esophageal cancer is the 8th most frequent cancer and the 6th most common cause of cancer deaths worldwide. Five-year survival rate for esophageal cancer patients is 19% and decreasing to 0.9% in advanced esophageal cancer patients. With the aggressive nature for esophageal cancer, most patients are initially diagnosed with advanced-stage, leaving fewer diagnosed early enough for successful treatment. Esophageal cancer is caused primarily by extrinsic factors and, to a lesser extent, by genetic factors.