Graphical representation of the method used to evaluate the Ki-67 index, quantified using the Image-Pro Plus 6.1 software. (A) Photomicrograph of the selected microscope field exhibiting Ki-67-positive nuclei in a carcinoma hot spot. (B) Selection of the immunostained nuclei (in red). (C) Selection of the unstained nuclei (in yellow). (D) Measurement of the ratio of the immunostained nuclear area (in red) and the entire nuclear area, expressed as the percentage of the immunostained area. This method allows the rapid inclusion of all nuclei in the measurement and enables areas with tissue artifacts to be discounted. Scale bar = 50 μm.