Other ATP-dependent chromatin regulators also appear to function as tumor suppressors in humans. Of note is CHD1, which is mutated in about 8 to 10% of cases of stomach cancer and colorectal cancer and is 22nd on Davoli et al.’s list of tumor suppressors (100). By contrast, BAF250a is 4th, BAF180 is 6th, BAF200 is 15th, and BAF250b (ARID1B) is 43rd. CHD1 is located on human chromosome 5q21, which is frequently deleted in prostate cancer and is required for androgen receptor–driven gene expression and the androgen-dependent translocation of the ERG gene (105–107). The observation (from cBio portal) that it is mutated in only 1 to 2% of prostatic cancers suggests that other genes located within the deleted region might contribute to its role in tumor suppression. Furthermore, unlike SMARCA4 (BRG1 or BAF190), there are no recurrent missense mutations in the ATPase domain of CHD1 in cancer that would indicate that this particular function is critical. A knockdown was reported to interfere with murine ES cell formation and to be required for pluripotency, but this has not been confirmed yet with a null mutation.
