MKI67 and breast cancer: For the 105 breast cancer lesions, pathologic evaluation of the Ki-67 ranged from 1 to 86 (median, 45); 35 lesions had a Ki-67 of less than 14 and were categorized as the low-proliferation group (Figure 3), and 70 had a Ki-67 of 14 or greater and were categorized as the high-proliferation group (Figure 4).