BACKGROUND Epithelial-mesenchymal transition (EMT) is critical for morphogenesis during embryonic development and is also implicated in the conversion of early-stage tumors into invasive malignancies. Recently, Twist has been identified to play an important role in EMTmediated metastatic progression of several types of human cancer. The present study examined the expression of Twist and evaluated its clinicopathologic significance in urothelial carcinoma of upper urinary tract. METHODS Immunohistochemical staining for Twist expression was performed on 70 upper urinary tract urothelial carcinomas (UUT-UCs) using tissue microarray. RESULTS Immunohistochemical staining for Twist was positive in 31/70 cases (44.3%) of UUT-UCs. Twist expression was associated with high-grade and advanced-stage (ISUP grade, p<0.01; stage, p=0.045). The patients with Twist positive-tumors revealed lower disease free survival rate than those with Twist negative-tumors (p<0.01). The overall survival for patients with Twist positive-tumors was slightly worse than the patients with Twist negative- tumors, but the difference was not statistically significant (p=0.12). CONCLUSION Our results suggest that Twist is a novel marker for advanced UUT-UC.