Abstract
A high prevalence of aberrant beta-catenin has been reported in radiation-associated thyroid tumors (RATT). CyclinD1 is a target activated by Wnt/beta-catenin. While,Pin1 promotes cyclinD1 expression and p53 phosphorylation induced by irradiation. This study aimed to elucidate whether Pin1 was involved in cyclinD1 and beta-catenin expression in RATT. We examined follicular adenomas (FA) and papillary carcinomas (PC). All PC displayed cyclinD1 overexpression and a cytoplasmic beta-catenin. Overexpression of cyclinD1 mRNA was observed in 45.5% of FA and 54.5% of PC. Correlation was revealed between cyclinD1 and Pin1/cytoplasmic/membrane beta-catenin expressions, and between Pin1 and cytoplasmic/membrane beta-catenin expressions in RATT. Any mutations of beta-catenin gene could not be detected. Western blot analysis demonstrated a high level of cyclinD1 and beta-catenin as well as Pin1 expressions in a PC cell line. This study supported a significance of cyclinD1 overexpression and aberrant beta-catenin in RATT. Pin1 may be an important factor to regulate cyclinD1 and beta-catenin in RATT. [J Radiat Res 44:396 (2003)]
