Background: The SWI/SNF-related, matrix-associated, actin-dependent regulators of chromatin (SMARC), also called BRG1-associated factors (BAFs), have been identified as components of the human SWI/SNF-like chromatin-remodeling protein complexes. SWI/SNF complexes possess ATPase and DNA helicase activity that promotes transcriptional activation of genes normally repressed by chromatin structure. ARID1B is a noncatalytic subunit that is a member of the ARID (AT-rich interactive domain-containing protein) family of DNA binding proteins. ARID1B is encoded by a gene independent from ARID1A and exhibits functionally distinct characteristics.