p53 mutations in tumors derived from irradiated human thyroid epithelial cells

A non-tumorigenic human thyroid epithelial cell line (HTori-3) has been tra nsformed into tumorigenic cells by exposure in vitro to alpha particles or gamma-radiation. These transformants were tumorigenic in athymic nude mice and tumors were transplantable into other nude mice. To further characteriz e processes involved in neoplastic progression, the tumor cell lines derive d from these radiation-induced primary tumors were screened for mutations i n the p53 tumor suppressor gene. p53 mutation was detected by single-strand conformation polymorphism (SSCP) analysis of exons 5 to 8 inclusive. Mutat ions detected by SSCP analysis were confirmed by sequencing. Mutations were detected in all four exons analysed, although there was no correlation bet ween dose, LET or mutation position or frequency. Mutations in p53 exons 6 and 7 have been reported in the childhood papillary thyroid carcinomas in B elarus presumably as a result of radioiodine fall-out. Similarly here, p53 mutations are induced experimentally during the development of human thyroi d tumors generated by irradiation of a human thyroid epithelial cell line i n vitro, (C) 1999 Elsevier Science B.V. All rights reserved.