title: Expression and localization of the homeodomain-containing protein HEX in human thyroid tumors.
abstract: Homeobox genes are involved in neoplastic transformation of both epithelial and hemopoietic tissues. The divergent homeobox gene HEX is expressed in the anterior visceral endoderm during early mouse development and in some adult tissues of endodermal origin, including liver and thyroid. Whereas a role in leukemyogenesis has been proposed already, few data are available on the involvement of HEX in human epithelial tumors. Herein, we analyzed HEX expression and subcellular localization in a series of 55 human thyroid tumors and in several tumoral cell lines. HEX mRNA was detected by RT-PCR either in normal tissues or in thyroid adenomas and differentiated (papillary and follicular) carcinomas. HEX mRNA was also expressed in most undifferentiated carcinomas. Subcellular localization of HEX protein was investigated by immunohistochemistry. In normal tissues and adenomas, HEX protein was present both in nucleus and cytoplasm. In contrast, both differentiated and undifferentiated carcinomas, as well as the tumoral cell lines investigated, showed HEX protein only in the cytoplasm. These findings suggest that regulation of HEX entry in the nucleus of thyrocytes may represent a critical step during human thyroid tumorigenesis.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, 33100 Udine, Italy.
authors.forename: Angela V
authors.initials: AV
authors.lastname: D'Elia
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tell
authors.forename: Diego
authors.initials: D
authors.lastname: Russo
authors.forename: Franco
authors.initials: F
authors.lastname: Arturi
authors.forename: Fabio
authors.initials: F
authors.lastname: Puglisi
authors.forename: Guidalberto
authors.initials: G
authors.lastname: Manfioletti
authors.forename: Valter
authors.initials: V
authors.lastname: Gattei
authors.forename: David L
authors.initials: DL
authors.lastname: Mack
authors.forename: Palmina
authors.initials: P
authors.lastname: Cataldi
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Filetti
authors.forename: Carla
authors.initials: C
authors.lastname: Di Loreto
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Damante
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D012333:RNA, Messenger / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000378:metabolism*; D014018:Tissue Distribution; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
chemical_list: C078492:HHEX protein, human; C513080:Hhex protein, mouse; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D014157:Transcription Factors