Patients with HER2 amplified breast cancer presented a significantly worse outcome for overall (HER2 dichotomised: HR = 2.07 (95% CI 1.33 to 3.21), p = 0.001; HER2 continuous: HR = 1.16 (95% CI 1.06 to 1.26), p = 0.001) and disease-free survival than patients with the non-amplified gene (Table 3 and Figure 5a2). This evidence concerns the gene ERBB2 and breast cancer.