In the ATEMPT trial, patients with T1N0 HER2+ early-stage breast cancer were randomized to T-DMI or paclitaxel + trastuzumab (TH), and rates of treatment-related amenorrhea among pre-menopausal women at 18 months were 24% after T-DM1 and 50% after TH (p=0.045) [39•]. This evidence concerns the gene ERBB2 and amenorrhea.