['Upper tract urothelial carcinoma (UTUC) is a clinically heterogeneous disease that lacks high-quality trials that provide definitive prognostic markers. Insulin-like growth factor messenger RNA binding protein 3 (IMP3) has been associated with outcomes in urothelial carcinoma of the bladder but was not yet studied in UTUC.', 'To evaluate the association of the oncofetal protein IMP3 with oncologic outcomes in patients with UTUC treated with radical nephroureterectomy (RNU).', 'We investigated the expression of IMP3 and its association with clinical outcomes using tissue microarrays constructed from 622 patients treated with RNU at seven international institutions between 1991 and 2008.', 'All patients were diagnosed with UTUC and underwent RNU.', 'Uni- and multivariable Cox regression analyses evaluated the association of IMP3 protein expression with disease recurrence, cancer-specific mortality, and all-cause mortality.'] Does insulin-like growth factor messenger RNA-binding protein 3 expression help prognostication in patients with upper tract urothelial carcinoma?