For instance, in a prospective randomized trial evaluating the prognostic and predictive value of Ki-67 comparing letrozole with tamoxifen as adjuvant endocrine therapy in postmenopausal women with early breast cancer, Viale et al. [80] examined a Ki-67 cutoff point of ≤11 and >11 in 4399 patients. This evidence concerns the gene MKI67 and breast cancer.