MTOR and breast cancer: This suggests that BCATs may regulate tumors through different signaling pathways in different breast cancer subtypes.60 Similarly, BCAT1, which is highly expressed in breast cancer cells, promotes mitochondrial production and function by activating the mTOR signaling pathway and ultimately promotes breast cancer cell growth.61 The mechanism of action of BCAAs and their metabolic enzymes and metabolites in different breast cancer subtypes still needs further study (Fig. 4).