Through a robust statistical approach, capturing flexible daily estimates of BCSM risk, rather than broadly grouped, discrete TTS intervals2,6,12,13, we found that patients with HR+/HER2− breast cancer experienced rapid exponential trajectory of TTS-associated mortality risk, as opposed to the slower linear growth seen for patients with HER2 + and HR−/HER2− breast cancer. The gene discussed is ERBB2; the disease is breast cancer.