ERBB2 and breast cancer: Therefore, the first main message from our analysis is that, during the oncofertility counselling of premenopausal women with HER2-positive early breast cancer, the discussion around the risk of gonadotoxicity with the proposed treatment as well the need for having access to the available strategies for ovarian function and/or fertility preservation should be driven mostly by the type of chemotherapy regimen proposed and by the age of the patient (i.e., the two most important determinants of this risk).