Pathogenesis of breast cancer and drug resistance in HER2-positive breast cancer brain metastasis appears partly to be driven by the activation of PI3K/AKT/mTOR pathway, suggesting that targeted inhibition of individual components in this pathway, including Akt and mTOR may be a potential strategy for HER2 positive breast cancer therapy (53, 54). Here, ERBB2 is linked to breast carcinoma.