MKI67 and gastrointestinal stromal tumor: Although the Kaplan-Meier survival analysis revealed no significant difference in the survival rate of patients with GIST using the classical cut-off of 5 H&E mitoses per 50 HPFs or the threshold value of 134.8 Ki-67-positive cells per mm2 (Fig. 2), the statistical analysis showed by trend an improved prognosis based on the image analysis of only three hot spots of Ki-67 IHC in Ki-67-low cases.