Rearrangements of the RET tyrosine kinase receptor gene (RET/PTCs) are found in 2.6–34% of human papillary thyroid carcinomas (PTC) and are even more prevalent in radiation-induced paediatric PTC (Baverstock et al, 1992; Kasakov et al, 1992). The gene discussed is RET; the disease is thyroid gland papillary carcinoma.