Abstract
Radiation-induced thyroid cancer studies have been one of the focuses of the International Medical Cooperation and Epidemiology project conducted in frame of Nagasaki University’s 21st Century COE program.
Papillary thyroid carcinoma (PTC) is a prototypic human malignancy known to develop with an increased rate in the individuals exposed to external or internal radiation, especially if exposure takes place at young age. Since the recognition of the phenomenon of radiation-induced thyroid cancer, extensive efforts have been made to elucidate its distinctive molecular features and to determine a “radiation signature”.
Analysis of mutational frequencies of PTC-specific oncogenes (ret/PTC, TRK, BRAF, RAS and Gsa) or TP53 tumor suppressor demonstrated patients’ age-associated trend for some of them but no correlation with radiogenic nature of PTCs was found. To learn more about individual genetic characteristics of PTC patients, a comparative pilot study was performed to profile SNPs in several DNA damage response genes (ATM, MDM2 and TP53). Initial results demonstrated that some polymorphisms display a weak association with certain age groups of radiation-related or spontaneous PTCs.
Results of molecular investigations as well as those of molecular epidemiology studies seeking to identify genes that modify susceptibility to radiation-induced thyroid carcinogenesis in humans will be discussed.
