The value of cytoplasmic Y-box-binding protein 1 as a prognostic marker for breast cancer in Korean

BACKGROUND The human Y-box-binding protein 1 (YB-1) is a member of the DNA/RNA-binding family of proteins that regulates transcription and translation of genes. Previous studies suggest that YB-1 may have an oncogenic role in various cancers. In this study, we evaluate the prognostic value of cytoplasmic YB-1 with respect to breast cancer. METHODS Immunohistochemical staining study was performed with YB-1 using tissue block from 233 patients with invasive ductal carcinoma. Patients were divided into two groups according to expression of cytoplasmic YB-1 in tumor cell (high versus low). The relationship between the expression of YB-1, clinicopathological characteristics and breast cancer prognosis was analyzed. RESULTS Hormone receptor negativity, worse histologic and nuclear grade, high tumor stage, lymphovascular invasion and high Ki67 (≥14 %) were related with the increased expression of cytoplasmic YB-1 in tumor cell (p < 0.05). Although there was no significant difference in relapse-free survival (RFS) between the two groups (p = 0.412), difference in overall survival (OS) was statistically significant (p = 0.035). In multivariate analysis for OS, YB-1 was an independent prognostic factor (p = 0.043). CONCLUSION This suggests that the increased expression of cytoplasmic YB-1 in tumor cells can be regarded as an independent prognostic factor for breast cancer, related to poor prognostics. Expression of cytoplasmic YB-1 in cancer cell could be used as an independent prognostic marker for predicting OS in breast cancer.