The recent ‘Rx for Positive Node, Endocrine Responsive Breast Cancer’ (RxPONDER) trial found that postmenopausal women diagnosed with hormone receptor positive (HR+), human epidermal growth factor 2-negative (HER2-), node-positive breast cancer with a 21-gene recurrence score (RS) of ≤ 25 could safely omit chemotherapy, while a chemotherapy benefit was observed among premenopausal women at all RS levels [1]. The gene discussed is ERBB2; the disease is breast cancer.