Wang et al (2000) demonstrated that cyclin D1 was more frequently overexpressed in more aggressive thyroid carcinomas such as anaplastic carcinoma, tall cell variant, and insular carcinoma. On the other hand, Goto et al (2001) showed that cyclin D1 was frequently overexpressed in thyroid carcinoma but rarely in benign adenoma. This evidence concerns the gene CCND1 and poorly differentiated thyroid gland carcinoma.