PBRM1是抑癌基因，编码蛋白是BAF180蛋白，其是核小体-重塑复合物的组分用于SWI/SNF转换。BAF180含有6个溴结构域，其与组蛋白尾部的赖氨酸残基结合。每个溴结构域的异常足以破坏蛋白质作为肿瘤抑制因子的功能。有研究表明BAF180是p53依赖性细胞衰老所需的关键组分之一。在乳腺癌细胞系中，BAF180被鉴定为可以诱导p21活性的关键启动子，进而作为细胞周期调节功能的关键组分。PBRM1截短变异不再能够结合和重塑p21基因座，导致细胞周期缺陷和异常细胞增殖。PBRM1活性的丧失也与染色体不稳定性有关，因为它不能促进凝聚力。

PBRM1 encodes a tumor suppressor and component of the SWI/SNF chromatin-remodeling complex. Inactivating mutations of PBRM1 are frequently found in renal carcinoma.The PBRM1 gene encodes the protein BAF180, which is a component of the nucleosome-remodeling complex switching defective/sucrose non-fermenting (SWI/SNF). Nucleosomes are histone octamers around which DNA is wrapped in order to regulate its exposure to transcription factors and RNA polymerases. Remodeling complexes such as the SWI/SNF family serve to loosen, reposition and break DNA/histone contacts ultimately rendering the DNA accessible to modulation. BAF180 contains 6 bromodomains, which bind to lysine residues in histone tails. Aberrations of each individual bromodomain are sufficient to disrupt the protein's function as a tumor suppressor. Specifically, one study demonstrated that BAF180 is among the key components required for p53-dependent cellular senescence. Additional work focusing on breast cancer cell lines identified BAF180 as a critical promoter in the induction of p21 activity, which functions as a key component of cell cycle regulatory functions. PBRM1 truncation mutants can no longer bind and remodel the p21 locus leading to cell cycle defects and aberrant cell proliferation. Loss of PBRM1 activity is also associated with chromosomal instability due to its inability to promote cohesion.

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