title: Sorting Nexin 2 (SNX2): a potential marker of active thyrocytes in normal and hyperfunctioning thyroid disorders.
abstract: Sorting nexins (SNXs) are a large, diverse group of cytoplasmic and membrane-associated proteins that function in a variety of cellular processes, including endocytosis, protein trafficking, and the retrieval of transmembrane proteins. In this study, we demonstrated that SNX2 is expressed in columnar and active thyroid follicular cells but not in flattened inactive thyrocytes. Morphometric analysis revealed a significant correlation between SNX2 positivity and columnar cell morphology. Immunohistochemical staining of serial sections of the thyroid tissue indicated that SNX2 localization was similar to sortilin, a protein expressed by active thyrocytes. Expression of SNX2 in thyrocytes is particularly marked and extensive in most hyperstimulated thyroid disorders, including Graves disease (diffusely SNX2 positive in 73.3% patients) and functioning nodules (93.8% patients). SNX2 immunolocalization in hyperstimulated follicular epithelial cells was specific among the SNXs family members examined. These results support the utility of SNX2 as a novel marker of active thyrocytes and reflect the endosomal trafficking activity in these cells.
authors.affiliation: *Department of Pathology, Division of Diagnostic Pathology †Department of Pathology, Division of Pathology, Kobe University Graduate School of Medicine ‡Department of Pathology, Kuma Hospital, Kobe, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Kanzawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hara
authors.forename: Shuho
authors.initials: S
authors.lastname: Semba
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokozaki
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Hirokawa
authors.forename: Tomoo
authors.initials: T
authors.lastname: Itoh
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002675:Child, Preschool; D011992:Endosomes / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006111:Graves Disease / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D021381:Protein Transport; D058305:Sorting Nexins / Q000235:genetics*; D013961:Thyroid Gland / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D016606:Thyroid Nodule / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000601:surgery
chemical_list: D015415:Biomarkers; C513979:SNX2 protein, human; D058305:Sorting Nexins