Expression of VEGFR and PDGFR-α/-β in 187 canine nasal carcinomas.

Radiotherapy represents the standard of care for intranasal carcinomas. Responses to tyrosine kinase inhibitors (TKIs) have been reported but data on expression of target receptor tyrosine kinases (rTKs) is limited. This study characterizes the expression of vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR)-α and PDGFR-β in canine intranasal carcinomas. Histological samples from 187 dogs were retrieved. Immunohistochemistry was performed using commercially available antibodies. Expression of rTKs was classified into weak, moderate or intense and additionally recorded as cytoplasmic, membranous, cytoplasmic-membranous, nuclear or stromal. VEGFR was expressed in 158 dogs with predominantly moderate expression (36.9%) and a cytoplasmic-membranous expression pattern (70.9%). PDGFR-α was detected in 133 with predominantly weak expression (57.9%) and cytoplasmic pattern (87.9%). PDGFR-β was identified in 74 patients with a predominantly moderate expression (17.6%) and cytoplasmic expression pattern (63.5%). Co-expression of rTKs was common. These results confirm expression of VEGFR, PDGFR-α and PDGFR-β in canine intranasal carcinomas and support the utility of TKIs.