Elevated AFP levels in adults are typically associated with hepatocellular carcinoma or yolk sac tumors, and secretion by CRC is rare, with only a few cases reported since the first description in 1985 [15,16]. AFP-producing gastrointestinal tumors may arise throughout the digestive tract but occur most frequently in the stomach (>80%) [15,17]. This evidence concerns the gene AFP and yolk sac tumor.