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

Abstract

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.

Y-Box binding protein 1 expression in breast cancer and its correlation with hormone receptors and other prognostic markers

“…Few other studies have suggested that YB1 acts as a promoter of Her2, and its expression leads to the clonal selection and expansion of Her2-positive cells. [ 25 26 ] Similar results were obtained in another study, which reported that YB1 directly binds to the Her2 promoter in cells where Her2 gene was amplified. It thus allowed the cells with Her2 amplification to slip through the cell cycle check points and promote tumor growth.…”

“…[ 8 ] In a similar study in 239 breast cancer cases, nuclear YB1 expression was found to be positive in 36.8% of cases. [ 25 ]…”

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

“…Nuclear expression of YB-1 was also significantly related with poor prognostic factors (ER and PR negativity, high histologic and nuclear grade, high Ki-67 expression) and poor OS (data were not shown). However, such an expression was observed in 26 out of 233 cases (11.2 %) and this was a relatively small proportion compared to previous studies [8, 11, 15]. Some previous studies reported that nuclear localization of YB-1 was induced by growth factors and cytokines and related with tumor progression [19–21].…”

“…Because our cases were composed of relatively early stage tumors compared to previous studies, there may be fewer cancer related deaths and recurrences compared to other studies [8, 11, 15]. Therefore, this study could not show the independent role of established prognostic factors except the nodal stage.…”

“…Previous studies showed that the localization of YB-1 in nucleus was associated with poor prognosis as well as with poor prognostic factors [8, 11, 15]. Some studies showed that the nuclear YB-1 expression was positively correlated with the HER2 expression and suggested the inhibition of YB-1 could be a good therapeutic target for HER2 type tumor [15–17].…”