Novel aspects of Wnt signaling in intestinal development and cancer

The gastrointestinal tract is a highly specialized organ system responsible for the processing of ingested food, including the uptake of nutrients and the removal of waste products. Each region of the digestive tract has its own specialized function and associated unique anatomy. The breakdown of food initiates in the oral cavity, after which the components are transferred via the esophagus to the stomach. In the stomach, the food components are processed into chyme, and thereby prepared for entrance into the small intestine. On its turn, the small intestine is responsible for the absorption of nutrients. The anatomy of the small intestine is very suitable for this function, given the enormous absorptive area that is provided by fingerlike protrusions called the villi (Figure 1A). After nutrient uptake in the small intestine, the digestion process continues in the large intestine, where water is absorbed and the remaining parts are prepared for elimination from the body.