ORIGINAL PAPER Journal of Pathology J Pathol 2011; 223: 72–80 Published online 29 October 2010 in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/path.2802 Micro-RNA signature of the epithelial–mesenchymal transition in endometrial carcinosarcoma Mar´ ıa ´ Angeles Castilla, 1# Gema Moreno-Bueno, 2# Laura Romero-P´ erez, 1 Koen Van De Vijver, 3 Michele Biscuola, 1 Mar´ ıa ´ Angeles L ´ opez-Garc´ ıa, 1 Jaime Prat, 4 Xavier Mat´ ıas-Guiu, 5 Amparo Cano, 2 Esther Oliva, 3 and Jos´ e Palacios 1 * 1 Department of Pathology, Hospital Universitario Virgen del Roc´ ıo-IBIS, Instituto de Biomedicina de Sevilla, Sevilla, Spain 2 Department of Biochemistry UAM, Instituto de Investigaciones Biom´ edicas ‘Alberto Sols’ (CSIC-UAM), Instituto de Investigaci´ on La Paz (IdiPAZ), Madrid, Spain 3 Department of Pathology, Massachusetts General Hospital, Boston, MA, USA 4 Department of Pathology, Hospital Sant Pau, Barcelona, Spain 5 Department of Pathology and Molecular Genetics, Hospital Universitari Arnau de Vilanova, University of Lleida, IRBLLEIDA, Lleida, Spain *Correspondence to: Jos´ e Palacios, Department of Pathology, Hospital Universitario Virgen del Roc´ ıo-IBIS, Instituto de Biomedicina de Sevilla, Sevilla, Spain. e-mail: jose.palacios.sspa@juntadeandalucia.es # These authors contributed equally to this study. Abstract Endometrial carcinosarcomas (ECSs) undergo a true epithelial-mesenchymal transition (EMT). The molecular determinants of the EMT in vivo are unclear, although a role for some miRNAs, mainly involving the miR-200 family, was recently suggested from in vitro cellular models. We analysed the microRNA (miRNA) signatures associated to EMT in human carcinosarcomas, and determined their relationships with EMT markers and repressors of E-cadherin transcription. The expression of E -, P - and N-cadherin, cadherin-11, p120, vimentin, SPARC, fascin and caveolin-1 was studied in a group of 76 ECS by immunohistochemistry. In addition, real-time PCR was used to measure the differences in the expression of 384 miRNAs, E-cadherin, cadherin-11, SPARC, SNAIL, ZEB1, ZEB2, TWIST-1, TCF4, TGFβ1 and TGFβ2 between the epithelial and mesenchymal components of 23 ECSs. A loss of epithelial characteristics, including cadherin switching and the acquisition of a mesenchymal phenotype, was accompanied by changes in the profile of miRNA expression and the up-regulation of all the E-cadherin repressors analysed. A greater than five-fold difference in the expression of 14 miRNAs between both neoplastic components was seen. Members of the miR-200 family were down-regulated in the mesenchymal part of the ECS. In addition, miR-23b and miR-29c, which are involved in the inhibition of mesenchymal markers, and miR-203, which is involved in the inhibition of cell stemness, were also down-regulated. Up-regulated miRNAs included miR-155, miR-369-5p, miR-370, miR-450a and miR-542-5p. These data suggest that in human ECS, the interplay between transcriptional repressors of E-cadherin and miRNAs provides a link between EMT-activation and the maintenance of stemness. Copyright  2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Keywords: miRNA; epithelial-mesenchymal transition; endometrial carcinosarcoma; differentiation; E-cadherin Received 6 July 2010; Revised 9 September 2010; Accepted 28 September 2010 No conflicts of interest were declared. Introduction Carcinosarcomas (CSs) are uncommon but aggressive neoplasias with a biphasic histology of carcinoma- tous and sarcomatous elements. Although they develop in different organs, they are most common in the endometrium, breast, lung, kidney and upper aerodi- gestive tract. Due to the intimate admixture of mor- phologically diverse malignant cells, the histogenesis of endometrial carcinosarcomas (ECSs) has long been a matter of debate [1,2]. However, the most favoured theory postulates that both elements originate from a single stem cell clone. From a biological point of view, the process by which malignant epithelial cells transdifferentiate to malignant mesenchymal cells could be considered a true epithelial–mesenchymal transition (EMT) in human neoplasias [3,4]. The EMT is a process of cel- lular transdifferentiation by which epithelial cells lose their polarity and cell–cell contacts, reorganize their cytoskeleton, acquire the expression of mesenchymal markers and manifest a migratory phenotype. The EMT occurs in three distinct settings with different func- tional consequences: type 1, embryonic EMT; type 2, associated with wound healing and tissue regeneration [5,6]; and type 3, occurring in epithelial cancer during Copyright  2010 Pathological Society of Great Britain and Ireland. J Pathol 2011; 223: 72–80 Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk www.thejournalofpathology.com