Cancer in your esophagus, the tube that runs from your throat to your stomach, is one of the most frequently reported and a leading cause of cancer deaths around the world. Most cases are reported in developing countries. Early esophageal cancer typically causes no symptoms. However, its chemical markers are present in the earliest stage. A new device being tested in England takes advantage of that to allow early detection of esophageal and other types of cancer. Faith Lapidus reports.