Epithelial-mesenchymal transition (EMT) is critical not only for morphogenesis during embryonic development but also the conversion of early-stage tumors into infiltrative phenotypes. The present study examines the expression of Twist, a highly conserved bHLH transcription factor that is known to promote EMT, and evaluated its prognostic significance in endometrial cancers. Tissue specimens from 70 patients with endometrial cancer who underwent primary surgery were immunohistochemically evaluated for Twist expression. A semi quantitative scoring system was developed based on the intensity and extent of cancer cells with Twist expression. Thirty-six patients (51%) exhibited high Twist expression and 34 (49%) had low expression. Most cases exhibited both cytoplasmic and nuclear staining mainly observed in cancer foci and, preferentially, at the margin but, in some cases, the stromal cells located adjacent to cancer foci as well. Among various clinical variables, high Twist expression was significantly associated with deep myometrial invasion (> 1/2) (P = .012) and concurrent with decreased E-cadherin expression (P < .001), a hallmark of EMT. In univariate survival analyses, both myometrial invasion and Twist expression influenced overall survival, but Cox multivariate analyses revealed that only Twist was an independent predictor of patient survival (hazard ratio, 5.12; P = .023). Thus, our data implies that high Twist expression is a potential novel prognostic factor for disease survival of endometrial cancer. Furthermore, the present study implicates Twist as a potential therapeutic target for this tumor type. (c) 2006 Elsevier Inc. All rights reserved.