Cancers of the gastrointestinal tract remain a major challenge for oncologists and other cancer specialists in the worldwide. This book is especially focused on the smooth muscle cell plasticity, hyperplasia and the associated with most frequent mesenchymal tumor, Gastrointestinal stromal tumor, that may occur anywhere in the Gastrointestinal tract, from esophagus to anus, encompass a heterogeneous and as yet incompletely understood. What is the origin of Gastrointestinal stromal tumor? It is included in the tumor processes next gen? What is the function of this gene during the development smooth muscle cells? You can find answers to these and many other questions in this book. This book is the sum up of work at Faculty of Medicine, INSERM U1046 in Montpellier and at Faculty of Medicine and Dentistry in Olomouc.