Interestingly, the analysis showed that BAG2 expression was not associated with tumor relapse in all HER2-positive breast cancer patients; however, when only those with chemotherapy were tested, it showed that high BAG2 expression was significantly associated with tumor relapse, indicating that BAG2 may be involved in the tolerance to chemotherapy, instead of HER2-targeting therapy (Figure S1A-B). Here, ERBB2 is linked to breast cancer.