Molecular subtype classification of urothelial carcinoma in Lynch syndrome

Lynch syndrome confers an increased risk for urothelial carcinoma (UC). Molecular subtypes may be relevant to prognosis and therapeutic possibilities, but have to date not been defined in Lynch syndrome-associated urothelial cancer. We aimed to provide a molecular description of Lynch syndrome-associated UC. Thus, Lynch syndrome-associated UC of the upper urinary tract and the urinary bladder were identified in the Danish hereditary non-polyposis colorectal cancer (HNPCC) register and were transcriptionally and immunohistochemically profiled and further related to data from 307 sporadic urothelial carcinomas. Whole genome mRNA expression profiles of 41 tumors and immunohistochemical stainings against FGFR3, KRT5, CCNB1, RB1, and CDKN2A (p16) of 37 tumors from Lynch syndrome patients were generated. Pathological data, microsatellite instability, anatomic location, and overall survival data was analyzed and compared with sporadic bladder cancer. The 41 Lynch syndrome-associated UC developed at a mean age of 61 years with 59% women. mRNA expression profiling and immunostaining classified the majority of the Lynch syndrome-associated UC as Urothelial-like tumors with only 20% being Genomically Unstable, Basal/SCC-like or other subtypes. The subtypes were associated with stage, grade, and microsatellite instability. Comparison to larger data sets revealed that Lynch syndrome-associated UC share molecular similarities with sporadic UC. In conclusion, transcriptomic and immunohistochemical profiling identifies a predominance of the Urothelial-like molecular subtype in Lynch syndrome and reveals that the molecular subtypes of sporadic bladder cancer are relevant also within this hereditary, mismatch-repair defective subset. This article is protected by copyright. All rights reserved.

Molecular oncology. 2018 May 23 [Epub ahead of print]

Christina Therkildsen, Pontus Eriksson, Mattias Höglund, Mats Jönsson, Gottfrid Sjödahl, Mef Nilbert, Fredrik Liedberg

The HNPCC register Clinical Research Center, Copenhagen University Hospital, Hvidovre, Denmark., Division of Oncology and Pathology, Institution of Clinical Sciences Lund University, Lund, Sweden., Institution of Translational Medicine Division of Urological Research, Lund University and Department of Urology, Skåne University Hospital, Sweden.