EGFR and thyroid cancer: Copy number increases have been found in different subtypes of thyroid cancer such as epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor A/B (PDGFRA/B), vascular endothelial growth factor receptor 1,2 (VEGFR1,2), mast/stem cell growth factor receptor kit (c-Kit) and metabotropic proto-oncogene receptor tyrosine kinase (MET).