Abstract 2430: The expression of BCL6 and ZEB family transcription factors and their correlation in breast cancers

Abstract

Abstract The proto-oncogene B-cell lymphoma 6 (BCL6) is an evolutionarily conserved zinc finger protein and a potent transcriptional repressor. It is also the master regulator of B-lymphocyte development. Emerging evidence indicates that BCL6 may play an important role in breast cancer progression. In this study, we investigated the expression of BCL6 and tis correlation with the expression of epithelial-mesenchymal transition (EMT)-associated transcription factors zinc finger E-box-binding homeobox 1 (ZEB1) and ZEB2 in invasive breast cancers. The mRNA and protein expression of BCL6, ZEB1 and ZEB2 were examined using in situ hybridization and immunohistochemistry, respectively, in 228 breast cancer patients and 80 patients with breast benign diseases. The association of BCL6, ZEB1 and ZEB2 expression with clinicopathological parameters and patient survival were analyzed. We found that the expression of BCL6, ZEB1 and ZEB2 protein and mRNA were significantly higher in breast cancer tissues than in breast benign disease tissues (P<0.05). The expression levels of BCL6, ZEB1 and ZEB2 were all positively correlated with the tumor size, lymph node metastasis and higher tumor stages (P<0.05). Furthermore, patients with BCL6, ZEB1 and ZEB2 protein-positive primary tumors were associated with a significant lower overall survival (OS) rate (P=0.001, 0.002 and 0.001, respectively) and post-operative relapse-free survival (RFS) rate (P=0.002, 0.001 and 0.003 for the expression of BCL6, ZEB1 and ZEB2, respectively). The mRNA expression of ZEB1 and ZEB2 were positively correlated with BCL6 mRNA expression (rs=0.326, P<0.001; and rs=0.382, P<0.001, respectively); the protein expression of ZEB1 and ZEB2 were also positively correlated with BCL6 protein expression (rs=0.449, P<0.001; and rs=0.669, P<0.001, respectively). These results indicate that BCL6, ZEB1 and ZEB2 may be as potential biomarkers for predicting invasion, metastasis and prognosis of breast cancer and that BCL6 may be a regulator of ZEB family transcription factors (ZEB1 and ZEB2). Note: This abstract was not presented at the meeting. Citation Format: Min Zhao, Lin Ang, Li Zheng, Jin Wang, Jin Huang, Hongguang Hu, Qiang Zou. The expression of BCL6 and ZEB family transcription factors and their correlation in breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2430. doi:10.1158/1538-7445.AM2017-2430