Differential expression of moesin in breast cancers and its implication in epithelial-mesenchymal transition

Aims: Moesin belongs to the ERM (ezrin, radixin and moesin) family. Recent in-vitro studies have shown the possible involvement of moesin in epithelial-mesenchymal transition (EMT), but correlating in-vivo evidence is lacking. Methods and results: To study the biological significance of moesin, we used immunohistochemistry to investigate the in-situ expression profiles of moesin in 322 breast carcinomas of different subtypes, including 23 cases of metaplastic carcinoma (MCB) which is pathogenetically considered to involve EMT. Moesin was highly expressed in 95.7% of cases of MCB, and in 16% of cases of invasive ductal carcinoma (IDC), but was negative in all other subtypes of breast carcinomas. In IDCs, moesin expression correlated positively with a high histological grade (P<0.001), basal-like phenotype (P<0.001) and poor overall survival (P =0.0263). Transfection of MCF7 cells with Snail, one of the key regulators of EMT, showed up-regulation of moesin at the transcriptional level. Finally, mRNA level of moesin correlated positively with Snail and EMT-related genes in a microarray data set using primary breast cancer samples. Conclusion: These results offer biological evidence of moesin as an EMT marker, support the association between moesin, Snail and EMT and suggest a role for moesin in breast cancer prognostication. ? 2012 Blackwell Publishing Ltd.