The dual role of BRD9 in cancer: Mechanistic insights and therapeutic prospects

Bromodomain-containing protein 9 (BRD9), an essential subunit of the switch/sucrose non-fermentable (SWI/SNF) remodeling complex, functions as a chromatin reader that recognizes acetylated lysine (Kac) residues to modulate chromatin structure and gene expression. Dysregulated BRD9 contributes to cancer cell proliferation, metastasis, and drug resistance, making it a promising therapeutic target. However, BRD9 also exerts a tumor-suppressive function in a context-dependent manner. A comprehensive elucidation of the ambivalent role and underlying mechanism of BRD9 in oncogenesis is urgently needed. In this review, we present a detailed overview of the current knowledge regarding the structure, dysregulation, and biological functions of BRD9 in cancer. We then systematically summarize the oncogenic roles and tumor-suppressive functions of BRD9 in different contexts. Finally, we explore the potential of BRD9 as an innovative therapeutic target and discuss its implications in clinical oncology, providing insights into emerging directions for novel cancer treatment strategies.