1. ¹Department of Surgery, Kuma Hospital, 8-2-35, Shimoyamate-dori, Chuo-ku, Kobe City 650-0011, Japan
2. ²Department of Pathology, School of Allied Health Science, Osaka University Faculty of Medicine, 1-7, Yamadaoka, Suita, Osaka 565-0871, Japan
3. ³Department of Pathology, Wakayama Medical College, Kimiidera 811-1, Wakayama City, 641-0012, Japan

Correspondence: Y Ito, E-mail: ito01@kuma-h.or.jp

Received 18 December 2001; Revised 9 April 2002; Accepted 11 April 2002.

Abstract

Cdc25B and cdc25A phosphates are prominent stimulators of cell cycle progression and recent studies have also suggested their oncogenic roles. To elucidate the role of these proteins in thyroid neoplasms, we immunohistochemically investigated their expression, and neither protein was expressed in normal follicular cells. Cdc25B was frequently overexpressed in follicular adenoma and minimally invasive follicular carcinoma, but the incidence was significantly lower in widely invasive follicular carcinoma. Furthermore, the cdc25B expression level significantly decreased with the dedifferentiation of thyroid carcinoma. Cdc25A overexpression was observed in high incidences in all types of thyroid neoplasms. These results suggest that cdc25B and cdc25A play oncogenic roles in thyroid follicules and that cdc25B works predominantly in the early phase of the progression of thyroid carcinoma, whereas cdc25A plays a fundamental role in the development of thyroid neoplasms.