Patient demographics, disease-free survival, and molecular alterations, including in <i>TP53</i>, <i>PIK3CA</i>, <i>TERT</i>, <i>MAP2K1</i> genes, and <i>ERBB2</i> gene amplifications, were assessed and compared to pure serous and pure endometrioid carcinomas.<h4>Results</h4>Patients with mixed and mixed-feature carcinomas were older (median age: 73 years) and had worse disease-free survival (median: 23 months) than those with pure endometrioid carcinoma (median: 48 months). The gene discussed is ERBB2; the disease is endometrioid adenocarcinoma.