NTRK1 and carotid body paraganglioma: It has been shown that carotid body paragangliomas in people, which are biologically similar to chemodectomas in dogs (5, 6) often overexpress VEGFR1, VEGFR2, PDGFRα, and PDGFRβ, making them potential targets for treatment with tyrosine kinase receptor inhibitors such as sunitinib (24).