[Radiation-induced thyroid cancers]

Human epithelial thyroid radiation-induced tumorigenesis is the most frequent radiation-induced tumorigenic process in man. Results of different studies, concerning the molecular mecanism(s) of epithelial thyroid radiation-associated tumorigenesis show : 1) that there is not a significant difference in the frequency of activation of ras, gsp and trk proto-oncogenes between radiation-associated and <> thyroid tumors; 2) the relevant role played by RET/PTC ret proto-oncogene activating rearrangements, in the development of radiation-associated thyroid tumors originated after therapeutic radiation (mainly PTC 1) or the atomic accident of Chernobyl (mainly PTC 3) and 3) suggest that the patients who develop thyroid tumors after a history of irradiation, show a genomic instability consisting in a DNA repair defect.