Gastroesophageal reflux disease (GERD) is a medical condition characterized by heartburn, a burning sensation often accompanied by a sour taste in the mouth. Heartburn occurs when stomach acid backs up from the stomach into the esophagus, the tube that carries food from the mouth to the stomach
http://blog.brandonhospital.com/2012/07/09/how-gerd-can-increase-your-chances-of-esophageal-cancer/