EZH2 Overexpression as a Useful Prognostic Marker for Aggressive Behaviour in Thyroid Cancer.
BACKGROUND/AIM
Enhancer of zeste homolog 2 (EZH2) is a member of the polycomb group of genes, which are key factors in the regulation of cell proliferation and differentiation. EZH2 is overexpressed in many malignancies. We analyzed EZH2 protein expression levels in different histological subtypes of thyroid cancer to examine its utility as a prognostic factor.


MATERIALS AND METHODS
We examined EZH2 protein expression by immunohistochemistry in tissue samples from 67 cases of poorly differentiated (PDTC) and 48 cases of anaplastic thyroid carcinoma (ATC), and in samples of adjacent normal and differentiated thyroid carcinoma (DTC). We examined differences in expression of EZH2 among various histological types of thyroid cancer, and the relationship between EZH2 expression and patient outcome.


RESULTS
EZH2 protein was expressed in PDTC and ATC, but not in normal thyroid gland or DTC. EZH-positivity increased in the order of DTC, PDTC, and ATC (p<0.01). Higher EZH2 expression correlated with poorer survival in PDTC (p=0.004), and a similar but non-significant trend was observed in ATC (p=0.166). Multivariate analysis identified EZH2 as an independent prognostic factor similar to metastatic status in the Japanese Society of Thyroid Surgery (JSTS) classification of PDTC.


CONCLUSION
EZH2 overexpression is associated with malignant potential in thyroid cancer, and may thus be a useful prognostic marker of aggressive thyroid cancer.
['Masudo|Katsuhiko|K|', 'Suganuma|Nobuyasu|N|', 'Nakayama|Hirotaka|H|', 'Oshima|Takashi|T|', 'Rino|Yasushi|Y|', 'Iwasaki|Hiroyuki|H|', 'Matsuzu|Kenichi|K|', 'Sugino|Kiminori|K|', 'Ito|Koichi|K|', 'Kondo|Tetsuo|T|', 'Nakamura|Yoshiyasu|Y|', 'Yoshihara|Mitsuyo|M|', 'Masuda|Munetaka|M|', 'Miyagi|Yohei|Y|']
D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D014408:Biomarkers, Tumor D002648:Child D000071221:Enhancer of Zeste Homolog 2 Protein D005260:Female D006801:Humans D007150:Immunohistochemistry D053208:Kaplan-Meier Estimate D008297:Male D008875:Middle Aged D011379:Prognosis D012189:Retrospective Studies D065646:Thyroid Carcinoma, Anaplastic D013964:Thyroid Neoplasms D055815:Young Adult
EZH2 Thyroid cancer prognostic factor epigenetics