Cytokeratin and vimentin expression in breast cancer

Background: The transition from epithelial keratin to mesenchymal vimentin expression marks an important step in the malignant progression of breast cancer. This study analyzed the clinical significance of cytokeratin and vimentin in patients with breast cancer. Materials and methods: Expression of cytokeratin and vimentin was evaluated by immunohistochemistry on paraffin-embedded tissue sections of patients with breast cancer. Results: Loss of cytokeratin was seen in 11% of the patients. A clearer trend towards loss of cytokeratin was observed in patients with stage IV disease and PR negativity. Weak cytokeratin expression was present in patients who developed recurrence or metastatic disease. Loss of cytokeratin was associated with reduced overall survival in univariate and multivariate analysis, gain of vimentin expression was seen in 57% of breast carcinoma patients. It was higher in patients with lymph node positivity, advanced stage, HER2 positivity, and disease recurrence or metastasis. Multivariate survival analysis indicated that gain of vimentin expression was associated with reduced relapse-free survival. Conclusion: Loss of cytokeratin and gain of vimentin expression are indicators of biologically aggressive breast carcinoma. (Int J Biol Markers 2009; 24: 38-46)