In addition in ACOSOG-Z1031, in line with the main results of the study, there was no difference in Ki67 decrease between letrozole, anastrozole, and exemestane, and again on-treatment Ki67 analysis was reportedly able to predict the primary endpoint of the trial i.e. it suggested that there were no statistically significant differences in tumour response between the three AIs [34]. Here, MKI67 is linked to neoplasm.