Endometrial carcinoma is one of the most common gynecological cancers. MicroRNA-21 (miR-21) is the most consistently overexpressed miRNA in almost all human cancer types, and it might be a useful clinical biomarker and therapeutic target. However, its precise localization and significance in endometrial carcinoma have not been clarified. This study aimed to examine miR-21 expression in endometrial carcinoma and reveal its clinicopathological importance. We investigated miR-21 expression by in situ hybridization (ISH) using locked nucleic acid (LNA)-modified probes in 230 endometrial carcinoma patients. We evaluated miR-21 expression in cancer cells and stroma separately. High miR-21 expression in cancer cells was significantly associated with higher histological grade and lymph node metastasis. In Kaplan–Meier analysis, high miR-21 expression in cancer cells was significantly associated with poor progression-free survival. In particular, in endometrioid carcinoma, high miR-21 expression in cancer cells was an independent prognostic factor associated with poor progression-free survival, as well as older age and higher International Federation of Gynecology and Obstetrics (FIGO) stage.

子宫内膜癌是最常见的妇科癌症之一。MicroRNA-21 (miR-21) 是几乎所有人类癌症类型中最一致的过表达 miRNA，它可能是有用的临床生物标志物和治疗靶点。然而，其在子宫内膜癌中的精确定位和意义尚未阐明。本研究旨在检查子宫内膜癌中 miR-21 的表达并揭示其临床病理学重要性。我们使用锁核酸 (LNA) 修饰的探针通过原位杂交 (ISH) 在 230 名子宫内膜癌患者中研究了 miR-21 的表达。我们分别评估了癌细胞和基质中的 miR-21 表达。癌细胞中 miR-21 的高表达与较高的组织学分级和淋巴结转移显着相关。在 Kaplan-Meier 分析中，癌细胞中 miR-21 的高表达与无进展生存率低显着相关。特别是在子宫内膜样癌中，癌细胞中的高 miR-21 表达是与无进展生存率差、年龄较大和国际妇产科联合会 (FIGO) 分期较高相关的独立预后因素。