The most commonly affected BAF subunit in cancer to date is ARID1A (BAF250A), which has now been found to be mutated in a wide variety of tumors including endometrial carcinoma (65), colon and rectal cancers (72), pancreatic cancer (73), transitional cell carcinoma of the bladder (74), gastric cancer (75, 76), cholangiocarcinomas (77), and childhood neuroblastoma (78). BAF250a and BAF250b are dedicated subunits that appear to have no life outside of BAF complexes, which is the case with all other subunits except BAF53a and β-actin, which have a fraction as monomers. BAF250A mutations occur throughout the length of the gene, without clustering to any one domain, and most appear to be frameshift mutations predicted to lead to a loss of function or alternative splicing. Missense mutations are also present, but only a few are repeated and hence they are not particularly informative with respect to function. Chandler and colleagues (79) have created mice with a point mutation in the Arid domain and showed that the Arid domain in mice is critical for the function of the protein, yet mutations in the
