The mammalian SWI/SNF chromatin-remodeling complex consists of 15 subunits encoded by 29 genes, some of which are recurrently mutated in human cancers including ARID1A, ARID1B, ARID2, PBRM1, SMARCB1, SMARCA4, and others [1–3]. This evidence concerns the gene ARID1A and cancer.