Modifications (e.g. shorter duration of chemotherapy such as 4 cycles of anthracycline or docetaxel plus cyclophosphamide or 12 cycles of weekly paclitaxel plus trastuzumab in HER2-positive breast cancer, no dose-dense or dose-intensified chemotherapy) of regimens used in older patients compared to standard chemotherapy in younger patients are also advisable [18]. This evidence concerns the gene ERBB2 and breast cancer.