title: Altered expression of key players in vitamin D metabolism and signaling in malignant and benign thyroid tumors.
abstract: 1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), the active form of vitamin D, mediates antitumor effects in various cancers. The expression of key players in vitamin D signaling in thyroid tumors was investigated. Vitamin D receptor (VDR) and CYP27B1 and CYP24A1 (respectively activating and catabolizing vitamin D) expression was studied (RT-PCR, immunohistochemistry) in normal thyroid, follicular adenoma (FA), differentiated thyroid cancer (DTC) consisting of the papillary (PTC) and follicular (FTC) subtype, and anaplastic thyroid cancer (ATC). VDR, CYP27B1, and CYP24A1 expression was increased in FA and DTC compared with normal thyroid. However, in PTC with lymph node metastasis, VDR and CYP24A1 were decreased compared with non-metastasized PTC. In ATC, VDR expression was often lost, whereas CYP27B1/CYP24A1 expression was comparable to DTC. Moreover, ATC with high Ki67 expression (>30%) or distant metastases at diagnosis was characterized by more negative VDR/CYP24A1/CYP27B1 staining. In conclusion, increased expression of key players involved in local 1,25(OH)(2)D(3) signaling was demonstrated in benign and differentiated malignant thyroid tumors, but a decrease was observed for local nodal and especially distant metastasis, suggesting a local antitumor response of 1,25(OH)(2)D(3) in early cancer stages. These findings advocate further studies with 1,25(OH)(2)D(3) and analogs in persistent and recurrent iodine-refractory DTC.
authors.affiliation: Laboratory for Experimental Medicine and Endocrinology, KU Leuven, Leuven, Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Clinckspoor
authors.forename: Esther
authors.initials: E
authors.lastname: Hauben
authors.forename: Lieve
authors.initials: L
authors.lastname: Verlinden
authors.forename: Annick
authors.initials: A
authors.lastname: Van den Bruel
authors.forename: Lieve
authors.initials: L
authors.lastname: Vanwalleghem
authors.forename: Vincent
authors.initials: V
authors.lastname: Vander Poorten
authors.forename: Pierre
authors.initials: P
authors.lastname: Delaere
authors.forename: Chantal
authors.initials: C
authors.lastname: Mathieu
authors.forename: Annemieke
authors.initials: A
authors.lastname: Verstuyf
authors.forename: Brigitte
authors.initials: B
authors.lastname: Decallonne
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018167:Receptors, Calcitriol / Q000096:biosynthesis / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D013250:Steroid Hydroxylases / Q000096:biosynthesis / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D014807:Vitamin D / Q000378:metabolism*; D065668:Vitamin D3 24-Hydroxylase
chemical_list: D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D014807:Vitamin D; D013250:Steroid Hydroxylases; C585549:CYP24A1 protein, human; D065668:Vitamin D3 24-Hydroxylase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase