HDAC1 and cancer: Twist-related protein 1 (Twist1), a transcription factor of the basic helix-loop-helix class, is reported to promotes cancer invasion, induces epithelial-mesenchymal transition (EMT) [39], and reduces ER transcript levels through interacting with HDAC1 at the ER promoter, leading to histone deacetylation and chromatin condensation [40].