Expression of Cytokeratin 8 (CK8) in Human Endometrium and Endometriosis

Cytokeratins are a multigene family of polypeptides expressed in distinct combinations along the various routes of epithelial differentiation. In endometrial cancer and cervical intraepithelial neoplasia/cervical squamous cell carcinoma, the expression of cytokeratins correlates with aggressive tumor features, lesion grade, and the International Federation of Gynecology and Obstetrics (FIGO) stage. Although the central elements involved in the pathogenesis of endometriosis are as yet unexplained, it is generally accepted that invasive mechanisms and hormonal effects influence endometriotic disease. On the basis of a preliminary microarray analysis showing increased mRNA expression of cytokeratin 8 in peritoneal endometriosis in comparison with eutopic endometrium, the present study therefore investigated the expression of CK8 in human eutopic and ectopic endometrium, using immunohistochemical staining. The results of our analyses points to a posttranscriptional regulation of cytokeratin 8 in endometriotic lesions possibly through noncoding miRNAs. Zusammenfassung Die Proteine der Zytokeratin-Multigenfamilie werden im Rahmen der epithelialen Differenzierung in verschiedenen Kombinationen exprimiert. Bei Endometrium- und Zervixkarzinomen korreliert die Expression von Zytokeratinen mit aggressiven Eigenschaften des Tumors, dem Grad der Läsion und dem FIGO-Stadium. Obwohl die zentralen Elemente der Pathogenese von Endometriose noch immer umstritten sind, so ist doch allgemein akzeptiert, dass die Krankheit durch invasive Mechanismen und hormonelle Einflüsse beeinflusst wird. Aufgrund von Microarray-Analysen, die eine erhöhte mRNA-Expression von Zytokeratin 8 (CK8) bei peritonealer Endometriose im Vergleich zu eutopem Endometrium vermuten ließen, untersuchte die vorliegende Studie die Expression von Zytokeratin 8 in eutopem und ektopem Endometrium mittels Immunhistochemie. Die Ergebnisse dieser Analysen deuten auf eine posttranskriptionelle Regulation von Zytokeratin 8 in Endometrioseläsionen z. B. durch miRNAs hin. Key words endometrium - adenomyosis - microarray Schlüsselwörter Endometrium - Adenomyose - Microarray

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