Although it may not be expressed in other normal tissues, CTEN expression has been found to increase significantly in many types of cancer including thymoma, gastric, colorectal, breast, lung, skin, pancreatic, and hepatocellular cancer [14, 15, 18–20, 25–32], suggesting that overexpression of CTEN in these organ tissues may play a critical role in tumorigenesis. This evidence concerns the gene TNS4 and thymoma.