Accumulating evidence suggests that oncogenic activation by a gain-of-function mutation in KIT, accompanying both canine cutaneous MCTs and human systemic mastocytosis, includes internal tandem duplications (ITD) of exon 11 and the insertion or deletion of exons 8, 9, 11 or 17 [9–12], which then suggests KIT as an attractive therapeutic target for mast cell neoplasms. Here, KIT is linked to mast cell neoplasm.