**Mast Cell Tumors Mast Cell Tumors**

Yosuke Amagai and Akane Tanaka Yosuke Amagai and Akane Tanaka

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/65797

#### **Abstract**

Mast cell tumor is one of the major cutaneous tumors in dogs. Though the etiology of MCTs is not completely understood, it becomes clear that approximately 10–20% MCTs express mutant KIT receptors with ligand‐independent phosphorylation. Tyrosine kinase inhibitors targeting KIT exert antitumor effects on malignant proliferation of mast cells with or without gene mutations. However, the efficacy of KIT inhibitors on dogs with MCTs has been limited. In this chapter, we would like to outline the general understand‐ ings of mast cells such as the process of its differentiation and proliferation, and what has been revealed regarding the mechanism of tumorigenesis and therapeutic approaches. In particular, KIT mutation‐related evidences and therapeutic approaches in the future are discussed.

**Keywords:** mast cell tumor, stem cell factor, KIT, tyrosine kinase inhibitor
