In the hormone receptor-negative group (irrespective of HER2 status), patients with PIK3CA-mutated tumours (n = 21 of 188, 11.2%) showed numerically fewer RFI-events (3 of 21 vs 43 of 167) consistent with a higher RFI probability (84.4% and 72.9%, resp.; adjusted HR 0.49, 95% CI 0.152–1.597; Fig. S1E). This evidence concerns the gene ERBB2 and neoplasm.