INFLUENCE OF DIFFERENT CELL STORAGE/CULTURE CONDITIONS ON SPONTANEOUS PROLIFERATION AND LEVEL OF TYROSINE KINASE RECEPTOR INHIBITION IN TWO FELINE INJECTION-SITE SARCOMA CELL LINES

A Scoping Review on Tyrosine Kinase Inhibitors in Cats: Current Evidence and Future Directions

Tyrosine kinase inhibitors (TKIs) have become invaluable in the treatment of human and canine malignancies, but their role in feline oncology is less defined. While toceranib phosphate and masitinib mesylate are licensed for use in dogs, no TKI is yet approved for cats. This review systematically maps the research conducted on the expression of tyrosine kinases in neoplastic and non-neoplastic domestic feline tissues, as well as the in vitro/in vivo use of TKIs in domestic cats. We identify and discuss knowledge gaps and speculate on the further research and potential indications for TKI use in cats. A comprehensive search of three electronic databases and relevant paper reference lists identified 139 studies meeting the inclusion criteria. The most commonly identified tumors were mast cell tumors (MCTs), mammary and squamous cell carcinomas and injection-site sarcomas. Based on the current literature, toceranib phosphate appears to be the most efficacious TKI in cats, especially against MCTs. Exploring the clinical use of TKIs in mammary carcinomas holds promise. Despite the progress, currently, the evidence falls short, underscoring the need for further research to discover new indications in feline oncology and to bridge the knowledge gaps between human and feline medicine.

Medical approach to the treatment of feline injection site sarcoma with masitinib: a case report

Feline injection site sarcoma is a common tumor among cats, for which existing medical treatments do not prove to be entirely satisfactory. In this tumor, the platelet-derived growth factor receptor, a tyrosine kinase receptor, is frequently hyperactivated. In the past, clinical case reports with imatinib, a tyrosine kinase inhibitor (TKI), have demonstrated tumoral stabilization. Here we describe the use of another TKI, masitinib, which specifically inhibits c-Kit, platelet-derived growth factor receptor, and Lyn, and is currently licensed for veterinary use in canine mast cell tumors. The therapeutic results were initially satisfactory, with regression of the tumor followed by tumoral recurrence which was stabilized and moderately reduced. Further studies are suggested, in order to evaluate the relevance of TKIs in the treatment and prevention of recurrences of feline injection site sarcoma. Tumoral stabilization by means of an inexpensive and reasonably well tolerated treatment would prove to be of true therapeutic relevance, in particular for inoperable feline injection site sarcomas. Another indication for such TKIs could be in preoperative treatment as a means of facilitating surgical excision by reduction of adhesions.