ARID1A and neoplasm: In most cases, ARID1A mutations are either frameshift or nonsense mutations, suggesting their role as tumor suppressor gene, and BAF250a—the protein encoded—is part of a multiprotein SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex involved in the regulation of cellular processes including differentiation, proliferation, DNA repair, and tumor suppression [121, 122].