For example, AZA-treatment of BC cells induce dormancy via a SMAD4-transcriptional programme that restores TGF-β-signalling, which promotes dormancy [101, 106]; however, in metformin-treated BC cells, the induction of dormancy has been attributed to increased mitochondrial respiration and increased oxidative stress [96]. This evidence concerns the gene TGFB1 and breast cancer.