ARID3B expression in primary breast cancer samples

Oğuz Erdoğan, Ayşe Selcen
ARID3B (AT-rich interaction domain 3) is a member of the family of ARID proteins, which constitutes evolutionarily conserved transcription factors implicated in normal development, differentiation, cell cycle regulation and chromatin remodeling. In addition, ARID3B has been linked to cellular immortalization, epithelial-mesenchymal transition (EMT) and tumorigenesis. Given the emerging roles of ARID3B in tumor development, we examined its expression in primary patient-derived breast cancer samples to further investigate and elucidate the role of ARID3B in cancer pathogenesis and progression. Therefore we used immunohistochemical (IHC) staining procedure using formalinfixed paraffin-embedded (FFPE) blocks of 63 primary breast cancer samples. We compared ARID3B IHC staining according to different cellular localizations with major prognostic factors of breast cancer. Our results show that ARID3B nuclear staining is positively correlated with ER status of the tumor and negatively correlated with tumor grade, mitotic activity and HER2 expression. This study is significant in terms of revealing an important and novel relationship between ARID3B expression and ER and HER2 expression in breast cancer. Further studies will reveal the functional significance of the correlation between ER, HER2 and ARID3B expression which may improve our current knowledge of this relatively novel but potentially interesting protein.