Heterochromatin protein 1 expression is reduced in human thyroid malignancy.
Owing to the loss of heterochromatin integrity that occurs during thyroid tumorigenesis, the expression of Heterochromatin Protein 1 isoforms HP1α and HP1β was assessed by immunohistochemistry in 189 thyroid tumors and non-neoplastic tissues. Expression of HP1β was significantly decreased in all thyroid lesions, except in follicular adenomas, when compared with matched adjacent normal tissue. This loss of HP1β expression may in part be caused by microRNA dysregulation. An example is miR-205, a microRNA that is abundantly upregulated in thyroid carcinomas and shown to reduce the expression of HP1β. In contrast to HP1β, HP1α expression was only reduced in metastatic carcinomas and poorly differentiated lesions. These results suggest the reduction of HP1β followed by a decrease in HP1α contributes to the pathogenesis of thyroid carcinomas, and their loss is a potential marker of thyroid malignancy and metastatic potential, respectively.
Department of Pathology, University of Washington, Seattle, WA, USA.
Maria S
MS
Tretiakova
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
Sarah D
SD
Bond
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
David
D
Wheeler
Lester and Sue Smith Breast Center and the Department of Pathology, Baylor College of Medicine, Houston, TX, USA.
Alejandro
A
Contreras
Department of Health Studies, University of Chicago, Chicago, IL, USA.
Masha
M
Kocherginsky
Department of Pathology, University of Chicago, Chicago, IL, USA.
Todd G
TG
Kroll
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
Tracy K
TK
Hale
D020413:3' Untranslated Regions / Q000235:genetics; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002460:Cell Line; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis* / Q000235:genetics; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics; D009362:Neoplasm Metastasis; D013961:Thyroid Gland / Q000378:metabolism* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
D020413:3' Untranslated Regions; D014408:Biomarkers, Tumor; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone; D008156:Luciferases; D035683:MicroRNAs; C000715593:CBX1 protein, human; C000715594:CBX5 protein, human; C534425:MIR205, human