title: Expression of p57/Kip2 protein in normal and neoplastic thyroid tissues.
abstract: p57 (Kip2) belongs to the Cip/Kip family and is one of the universal negative regulators of the cell cycle. In this study, we investigated the p57 expression of various types of thyroid neoplasm. p57 overexpression was observed in only 4.2% of normal thyroid tissues. In follicular adenoma and minimally invasive follicular carcinoma, p57 was overexpressed in 100% and 91.7% of the cases, respectively. However, its incidence was significantly lower (p<0.0001) in widely invasive follicular carcinoma, of which only 36.4% overexpressed p57. This phenomenon was seen in 63.1% of papillary carcinoma and 13.3% of anaplastic (undifferentiated) carcinoma. Furthermore, poorly differentiated and undifferentiated carcinoma more frequently lacked p57 expression (p<0.0001). These results suggest that the down-regulation of p57 may play a role in the dedifferentiation of thyroid carcinoma and in follicular carcinoma mutating to be more invasive.
authors.affiliation: Kuma Hospital, 8-2-35 Shimoyamate-Dori, Chuo-ku, Kobe City 650-0011, Japan. ito01@kuma-h.or.jp
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshida
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakano
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Yokozawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hirai
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuzuka
authors.forename: Nariaki
authors.initials: N
authors.lastname: Matsuura
authors.forename: Kanji
authors.initials: K
authors.lastname: Kuma
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
mesh_terms: D002454:Cell Differentiation; D050761:Cyclin-Dependent Kinase Inhibitor p57; D015536:Down-Regulation; D006801:Humans; D007150:Immunohistochemistry; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D013961:Thyroid Gland / Q000378:metabolism* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: C493964:CDKN1C protein, human; D050761:Cyclin-Dependent Kinase Inhibitor p57; D009687:Nuclear Proteins