TGFB1 and breast cancer: Regarding breast cancer, mir-34a has already been proven to regulate cell proliferation, differentiation, epithelial-mesenchymal-transition, apoptosis, cell cycle arrest and to reverse drug resistance, after interaction with significant signaling pathways such as MET, p53, NOTCH, TGF-β, PRKD1 and BCL-2 pathways [53–56].