A total of 5598 patients with HR + /HER2- BC (as per initial local assessment) from the screening cohort of WSG-ADAPT-HR + /HER2-, 2162 patients with HR + /HER2- and 430 patients with HR-/HER2- tumors from the adjuvant WSG-PlanB trial and 336 patients from the WSG-ADAPT-TN trial were evaluated. Here, ERBB2 is linked to breast cancer.