A 40-year-old female presents to your endocrinology office complaining of a ‘ball in my neck’. She noticed a lump in her anterior neck approximately 3 months ago. Since that time, it has been slowly increasing in size. She has some neck pain, dysphagia, odynophagia, cough, weight loss, fever, and chills for the last 3 weeks. She immigrated to the United States from Kiev, Ukraine during the Russo-Ukrainian War, which started in 2014. When the Chernobyl disaster occurred on April 26,1986 she was two years old and was exposed to the radioactive material released into the environment. On physical examination, you feel a lump of 3 cm by 6 cm in the right part of her thyroid gland. Fine needle biopsy showed single layers of thyroid cells arranged in avascular projections or papillae; there are laminated calcified spheres at the tip of papillary projections. The nucleus is significantly larger than normal nuclei and appears optically clear. The chromatin, the genetic material within the nucleus, is condensed and forms a distinct, sharp rim around the periphery of the nucleus. You considered targeted therapy for this patient with Lenvatinib (Lenvima). Which of the following is the target of this agent?
