Since we detected KIT expression in the tumor tissue and it has been reported that the presence of a mutation in KIT is associated with a higher likelihood of response to toceranib in canine mast cell tumor [5], we subsequently analyzed the nucleotide sequence of KIT. Total RNAs were extracted from the tumor FNA samples that had been collected from the gingival mass and right submandibular lymph node using RNA-STAT 60 (Tel-Test, Friendswood, TX, USA). The gene discussed is KIT; the disease is mast cell neoplasm.