ERBB2 and breast cancer: However, despite the majority of young patients with localized early‐stage breast cancer receiving radiotherapy, the effect of HoR and HER2 status on benefit of RT in early‐stage breast cancer has not been integrated much.15 Thus, this is the first study comparing the RT benefit in young women with localized early stage breast cancer according to molecular subtypes, which could help predicting RT response and improve patient's survival by adjusting treatment strategies for individuals in the future.