With adjustment for all other factors shown in Table 1, apart from receipt of chemotherapy, the breast cancer mortality rate ratios were 1.00 and 1.05 for Ki67 scores of 0%-5% and 6%-29%, whereas for Ki67 scores of 30%-100% the rate ratio was 1.98 and the corresponding adjusted 8-year cumulative breast cancer mortality risks were 3.4% (95% CI = 2.8% to 4.1%), 3.5% (95% CI = 3.0% to 4.1%) and 6.6% (95% CI = 5.6% to 7.7%) (Figure 3, B, middle panel). This evidence concerns the gene MKI67 and breast cancer.