MKI67 and breast cancer: Taking into account the groupings in published BC studies [50,51,52,53,54], the BC patients in our cohort were stratified into groups with increasing Ki-67 values: group I (Ki-67 < 14%); group II (≥14 to ≤25%); group III (> 25 to ≤50%); and group IV (>50 to ≤100%) (Figure 4A).