The prognostic significanc of epithelial-mesenchymal transition in breast cancer

Background: This study investigates the influence of epithelial-mesenchymal transition on prognosis in breast cancer. Materials and Methods: Eighty breast carcinomas as well as 6 breast cancer cell lines were analysed immunohistochemically for the expression of epithelial keratins (K) K8, K19 and mesenchymal vimentin. Protein expression was correlated with histopathological factors and clinical follow-up. Results: Suppression of K8 and K19 occurred in the majority of the tumours (72.5% and 65%), while aberrant expression of vimentin was found in 21.2% of the tumours. Suppression of K8 as well as expression of vimentin was significantly correlated with short survival (p<0.004 and p<0.006). Moreover HER2 overexpression significantly correlated with K19 (p<0.0004) and vimentin (p<0.0005). In cell lines with increasing invasive potential, epithelial keratins were lost in favour of mesenchymal vimentin. Conclusion: The transition from epithelial keratin to mesenchymal vimentin expression marks an important step in the malignant progression of breast cancer.