Introduction Feline cutaneous mast cell tumours (cMCTs) are characterized by a variable biologic behaviour. Development of multiple cutaneous nodules and concurrent visceral involvement, along with inconsistency of conventional prognostic aids, justify present uncertainty in differentiating benign from malignant forms. c-kit proto-oncogene activating mutations have been reported in 68% of feline MCTs, however their prognostic relevance has not been determined. This is a prospective study performed on feline cMCTs with variable clinical presentation to assess whether KIT immunohistochemical overexpression can be regarded as indicative of c-kit mutations, and evaluate their relationship with disease progression. Materials and Methods Cats with a histological diagnosis of cMCT in the absence of visceral involvement were enrolled. Patients underwent surgery and were followed for at least 6 months. KIT/CD117 immunohistochemistry and c-kit mutation analysis (exons 8,9,11) were performed on tumour samples and correlated with DFI and OS. Results Twenty-one cats with 11 solitary, 4 multiple, and 6 disseminated cMCTs were included. Determinations were performed on 28 tumour samples. KIT cytoplasmic expression was observed in 20 tumours, showing a shorter DFI (P=0.013) and OS (P=0.04). c-kit encoding mutations were detected in 58% of cases (exon 8, 12%; exon 9, 46%; exon 11, 4%), but they were not directly correlated with clinical behaviour. Conclusion c-kit mutations occur frequently in feline cMCT, and their incidence is higher among tumours with a CD117 overexpression, but their prognostic relevance needs to be assessed in a larger series. Multiple nodules from any one cat did not harbour the same mutations, suggesting that they may represent separate events.

KIT receptor tyrosine kinase dysregulation in feline cutaneous mast cell tumour

SABATTINI, SILVIA;GENTILINI, FABIO;BETTINI, GIULIANO
2012

Abstract

Introduction Feline cutaneous mast cell tumours (cMCTs) are characterized by a variable biologic behaviour. Development of multiple cutaneous nodules and concurrent visceral involvement, along with inconsistency of conventional prognostic aids, justify present uncertainty in differentiating benign from malignant forms. c-kit proto-oncogene activating mutations have been reported in 68% of feline MCTs, however their prognostic relevance has not been determined. This is a prospective study performed on feline cMCTs with variable clinical presentation to assess whether KIT immunohistochemical overexpression can be regarded as indicative of c-kit mutations, and evaluate their relationship with disease progression. Materials and Methods Cats with a histological diagnosis of cMCT in the absence of visceral involvement were enrolled. Patients underwent surgery and were followed for at least 6 months. KIT/CD117 immunohistochemistry and c-kit mutation analysis (exons 8,9,11) were performed on tumour samples and correlated with DFI and OS. Results Twenty-one cats with 11 solitary, 4 multiple, and 6 disseminated cMCTs were included. Determinations were performed on 28 tumour samples. KIT cytoplasmic expression was observed in 20 tumours, showing a shorter DFI (P=0.013) and OS (P=0.04). c-kit encoding mutations were detected in 58% of cases (exon 8, 12%; exon 9, 46%; exon 11, 4%), but they were not directly correlated with clinical behaviour. Conclusion c-kit mutations occur frequently in feline cMCT, and their incidence is higher among tumours with a CD117 overexpression, but their prognostic relevance needs to be assessed in a larger series. Multiple nodules from any one cat did not harbour the same mutations, suggesting that they may represent separate events.
Proceedings of the 2nd World Veterinary Cancer Congress
77
77
Sabattini S.; Guadagni M.; Turba M.E.; Gentilini F.; Bettini G.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/119655
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