RET positive (RET+ve) thyroid cancer is a rare type of cancer where there is a change or mutation in a specific gene known as RET. Normally, the RET gene is responsible for providing instructions for making a protein that’s involved in signaling within cells. In the presence of a mutation in the RET gene, the protein is made incorrectly and causes an abnormal growth of cells. Patients can have one of two types of mutations in the RET gene: a fusion mutation or a point mutation. Fusion mutations in RET can lead to thyroid cancers such as papillary, differentiated, anaplastic, or Hurthle cell. Point mutation in RET can lead to medullary thyroid cancer (MTC). Once the presence of a mutation in the RET gene is identified, treatment can be tailored to focus on that specific gene.