This study sought to determine whether there is a significant difference in immunohistochemical expression of commonly studied biomarkers in endometrial cancer window studies, including Ki-67, phosphorylated markers of the PI3K-Akt-mTOR and insulin signaling pathways and hormone receptors between an endometrial biopsy taken immediately prior to the start of surgery and the hysterectomy specimen. This evidence concerns the gene MKI67 and endometrial cancer.