The association of the Ki67 and braest cancer prognosis is still a matter of great debate, many articles studies this correlation with various conclusions, and most agree that this debate is still open and more studies are still done regarding this subject, a meta-analysis study was done which included 64,196 breast cancer patients, the authors studied the cut off of the level of Ki67 which is associated with high fatality rate, they concluded that the cut off level of 25% was associated with higher fatality rate then patients with lower levels [7,[18], [19], [20]]. This evidence concerns the gene MKI67 and breast cancer.