Gastrointestinal stromal tumour lacking mutations in the KIT and PDGFRA genes in a cat

• Published in: Journal of small animal practice Vol. 63; no. 3; pp. 239 - 243
• Main Authors: Fujii, Y., Iwasaki, R., Ikeda, S., Chimura, S., Goto, M., Yoshizaki, K., Sakai, H., Ito, N., Mori, T.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-03-2022; Wiley Subscription Services, Inc
• Subjects: Animals; Cat Diseases - drug therapy; Cat Diseases - genetics; Cats; Gastrointestinal cancer; Gastrointestinal Stromal Tumors - drug therapy; Gastrointestinal Stromal Tumors - genetics; Gastrointestinal Stromal Tumors - veterinary; Genetic analysis; Mutation; Protein Kinase Inhibitors - therapeutic use; Protein-tyrosine kinase; Proto-Oncogene Proteins c-kit - genetics; Proto-Oncogene Proteins c-kit - metabolism; Proto-Oncogene Proteins c-kit - therapeutic use; Receptor, Platelet-Derived Growth Factor alpha - genetics; Tumors
• ISSN: 0022-4510; 1748-5827
• DOI: 10.1111/jsap.13416

Molecular subtyping in gastrointestinal stromal tumours is a useful method for predicting the efficacy of treatment using tyrosine kinase inhibitors in humans. However, owing to the paucity of reports on mutational analyses, the association between genetic mutations and the therapeutic response to tyrosine kinase inhibitors remains unclear in feline gastrointestinal stromal tumours. In this report, we describe the case of a cat with a gastrointestinal stromal tumour which was unresponsive to tyrosine kinase inhibitors. A mutational analysis revealed that the cat lacked mutations in both the KIT and platelet‐derived growth factor receptor‐alpha (PDGFRA) genes. Our findings are consistent with the fact that KIT/PDGFRA wild‐type gastrointestinal stromal tumours are less responsive to tyrosine kinase inhibitors in humans. This signifies the need for further evaluation and possibly individualised treatment for gastrointestinal stromal tumours in cats on the basis of mutational analyses.