Expression of Y-Box-binding protein 1 in Chinese patients with breast cancer

The purpose of this study was to investigate the expression of Y-Box-binding protein 1 (YB-1) in breast cancer and its correlation with clinicopathological characteristics and prognosis. Paraffin sections were retrospectively collected from 239 cases of stage I–III breast cancer patients and 30 healthy females who received surgery between January 2000 and December 2004 in the Chinese People’s Liberation Army General Hospital. The protein expression of YB-1 was detected by immunohistochemistry. The expression difference between the two groups and the correlation between YB-1 expression and clinicopathological characteristics and breast cancer prognosis were analyzed. Within the breast cancer group, YB-1 was expressed in the cytoplasm in 100.0% (239/239) of cases and in the nucleus in 36.8% (88/239) of cases. Within the control group of normal breast tissue, YB-1 was expressed in the cytoplasm in 100.0% (30/30) of cases and in the nucleus in 16.7% (5/30) of cases. The expression of YB-1 in the nucleus of breast cancer cells was significantly higher than that in normal breast tissue (P = 0.029). The expression of YB-1 in the nucleus of breast cancer cells positively correlated with the Scarff–Bloom–Richardson grade (P = 0.007) and HER-2 expression (P = 0.005), negatively correlated with ER expression (P = 0.004), and was independent of the age, menstrual status, pathological type, tumor size, lymph node status, presence of thrombosis, PR expression, and EGFR expression. The 5-year disease-free survival (DFS) and overall survival (OS) of patients with positive YB-1 expression in the nucleus were significantly lower than those of patients who were negative for nuclear YB-1 expression, and the difference was statistically significant (DFS 65.9% vs. 82.1%, P = 0.000; OS 79.5% vs. 92.1%, P = 0.000). Multivariate analysis suggested that the expression of YB-1 in the nucleus is an independent prognostic factor that affects DFS and OS in breast cancer patients (DFS P = 0.015; OS P = 0.035). In conclusion, the expression of YB-1 in the nucleus is related to carcinogenesis and the development of breast cancer. Therefore, YB-1 is an important molecular marker that can be used to predict breast cancer prognosis.