RET and neoplasm: A higher incidence of RET/PTC rearrangement is seen in children, and upon exposure to radioactive iodine isotopes [109], for instance, RET/PTC rearrangements were identified in 51.3–77% of tumor specimens collected from 5–18-year-old children exposed to radiation after Chernobyl reactor meltdown, while in non-exposed children, their prevalence was below 40% [109].