UpHER2 to one-third of all breast cancers are classified as the aggressive HER2-positive subtype, which is associated with a higher risk of recurrence compared to HER2-negative breast cancers. The HER2 hyperactivity associated with this subtype drives tumor growth by up-regulation of mTOR pathways and metabolic adaptation. Combination therapies that simultaneously target HER2 and mTOR improve clinical outcomes compared with HER2 inhibition alone. Drugs that mimic glucose deprivation in HER2-positive breast cancer patients have not been evaluated; however, preclinical studies have shown that the growth of HER2-positive breast tumors is reduced in response to combining the glycolytic inhibitor 2-DG with mTOR inhibitorsis a member of the epidermal growth factor (EGF) receptor family comprising EGFR/ErbB1, HER2/ErbB2, HER3/ErbB3, and HER4/ErbB4. EGF receptor family proteins encode for transmembrane receptors consisting of the extracellular ligand binding, lipophilic transmembrane, and cytoplasmic tyrosine kinase domains. Ligand binding to EGF receptors activates their hetero- or homodimerization whereby one EGF receptor will phosphorylate the other on a tyrosine, allowing cytoplasmic signaling complexes to bind to the EGFR dimer.