ObjectivesThe aim of this study was to evaluate the immunohistochemical (IHC) expression of Ki-67, estrogen receptors α (ERsα), and progesterone receptors (PRs) in high-risk endometrial cancer patients and to assess their prognostic impact.Methods/MaterialsImmunohistochemical expression of Ki-67, ERsα, and PRs was evaluated in primary untreated endometrial cancer. The correlation among IHC staining and risk factors of recurrence such as age, Federation International of Gynecology and Obstetrics stage, grading, depth of invasion, and metastatic spread was assessed.ResultsEighty-two patients were available for the analysis. Mean ± SD age was 65.05 ± 10.48 years. The IHC assessment revealed a lack of ERα in 46.3% and of PR in 48.7% as well as a high Ki-67 in 31.7%. Loss of ERα and PR was associated with a significant higher rate of advanced stage of disease, a higher frequency of G3 tumors, and a myometrial invasion greater than 50%. A strong Ki-67 expression correlated with a deeper myometrial invasion. Analysis of the interrelationship between receptor immunonegativity revealed a relevant association of ERα immunolocalization with PR and with a high Ki-67 expression. The present study also showed that loss of ERα (P = 0.003), advanced Federation International of Gynecology and Obstetrics stage (P < 0.001), and high Ki-67 (P = 0.004) were independent prognostic factors of a shorter disease-free survival. Importantly, loss of ERα, loss of PR, and a high Ki-67 were correlated with a higher incidence of distant recurrence.ConclusionsA systematic immunohistochemistry should be a key step in the therapeutic algorithm and could contribute to the identification of high-risk tumors.