HDAC1 and breast carcinoma: Our group has previously found that MeCP2 can bind the promoter of claudin-6 in breast cancer cell line MCF-7 (data unpublished), A number of studies have shown that MeCP2 is responsible for the initial recruitment of HDAC1, Sin3A and HDAC2, forming a tumor suppressor complex and were essential for MeCP2-mediated tumor suppression [36,37].