MTOR and breast cancer: For instance, tyrosine kinase inhibitors (lapatinib, neratinib, and tucatinib) and antibody-drug conjugate (trastuzumab deruxtecan: T-DXd) showed good antitumor effects against trastuzumab-resistant cells [14], and the use of PI3K/AKT/mTOR inhibitors such as Copanlisib have been shown to restore lapatinib sensitivity in breast cancer [15].