Aim of this pilot study is to describe the molecular profile of UTUC and investigate eventual correlation between immunohistochemical (IHC) expression of Nectin-4 and DNA mismatch repair (MMR) proteins (MLH1, MHS2, MSH6 and PMS2) in UTUC samples. This evidence concerns the gene MLH1 and renal pelvis/ureter urothelial carcinoma.