The prognostic significance of epithelial-mesenchymal transition in breast cancer.

This study investigates the influence of epithelial-mesenchymal transition on prognosis in breast cancer. 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. 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. The transition from epithelial keratin to mesenchymal vimentin expression marks an important step in the malignant progression of breast cancer.