Proportion of patients with relapse-free survival in each of the three cluster groups. Kaplan–Meier curves and the fitted curves under the Cox proportional hazards model are shown, with the data stratified by morphological type (GI, GII and GIII IDC and ILC). Group 1 (green) comprises principally cancers with loss of the whole chromosome arm, Group 2 (brown), cancers principally with gain and Group 3 (red), cancers principally with no change. The fitted curves for each group are purple, blue and yellow, respectively. Cancers with mixed gains, losses and no change are split among the three groups. The Cox regression model estimates a relative hazard ratio of 1.70 (95% CI 1.08–2.66, P=0.020).