Elevated Nuclear YB1 Expression Is Associated with Poor Survival of Patients with Early Breast Cancer

Background: Y-Box Binding (YB1) protein represents a multifunctional protein, which plays a significant role in processes of proliferation, apoptosis and control of tumour cell response to toxic agents, including chemotherapy. The present study aimed at evaluating the prognostic significance of YB1 expression in breast cancer. Materials and Methods: We analyzed nuclear and cytoplasmic expression of YB1 in 101 patients with stage II breast cancer, with 17 years of follow-up. Immunohistochemical reactions were performed on paraffin sections of primary tumours, using monoclonal antibodies against YB1. Results were tested for their correlation with clinical and pathological data. Results: Patients with a pronounced expression of the nuclear form the YB1 protein demonstrated a highly significant shortening of disease-free survival, disease-specific survival and overall survival. The prognostic value of YB1 was also corroborated by multivariate analysis. Conclusion: We demonstrated that high nuclear expression of YB1 is associated with poor survival of patients with early-stage breast cancer.