Excluding six organoids for which polyclonal origins were suspected and another with a germline CDH1 mutation, we finally evaluated somatic mutations for 64 organoids established from six pre- (n = 20) and nine postmenopausal (n = 32) patients with breast cancer and 12 from six healthy women (Fig. 1a and Extended Data Figs. 1 and 2). This evidence concerns the gene CDH1 and breast carcinoma.