In a study by Tan et al.[88], the silencing of PPP2R2B by DNA hypermethylation was found to be accompanied by mTOR inhibitor resistance, while Bao et al.[102] demonstrated that PPP2R2B downregulation is associated with poor prognosis in HER2+ BC and resistance to HER2-targeted therapy, including both lapatinib and trastuzumab. Here, MTOR is linked to breast cancer.