MKI67 and breast cancer: However, when we compared breast cancers with higher Ki67 expression (score ≥0.3) with cancers with lower or negative Ki67 expression (score <0.3), the levels of mPRα expression and mPRα-HiEx rate were both significantly higher in former cancers (1.30±0.1 vs. 0.97±0.08, P=0.01, 59.09% vs. 18.75%, P=0.0007).