SIRT1 and breast cancer: However, ZEB1 can also repress CDH1 independent of CtBP, for example by interaction with BRG1, a SWI/SNF chromatin‐remodeling protein.[10] An alternative co‐repressor is BIG1/SMARCA4, and genomic loss of SMARCA4 has been linked to mesenchymal change and therapy response in lung and breast cancers.[92] The canonical role of ZEB1 as a suppressor of CDH1 has been demonstrated in metastatic prostate cancer,[93] where it is required for SIRT1 recruitment, mediating deacetylation of histone H3 to block RNAPol recruitment and causing transcriptional repression.