Differentially Expressed MicroRNA in Urothelial Carcinoma, Adenocarcinoma, and Squamous Cell Carcinoma of the Urinary Bladder
Mei Lin Z Bissonnette, Masha Kocherginsky, Gary D Steinberg, Kevin P White, Gladell P Paner. University of Chicago, Chicago, IL
Background: The vast majority (90%) of bladder carcinomas are urothelial carcinomas (UroCA). Of the uncommon histological types of bladder carcinoma, squamous cell carcinoma (SCC) (up to 5% in Western countries) and adenocarcinoma (AdenoCA) (2%) are the most common, which usually present at a higher stage. Currently, the prognostic significance and response to treatment of SCC and AdenoCA compared to UroCA is still not clear. In this study, we analyzed the miRNA expression of these 3 tumor types and normal urothelium to determine if there is genomic distinction in addition to the morphologic differences among these entities.
Design: Archival formalin-fixed paraffin embedded material of 9 invasive primary bladder carcinomas and 3 normal urothelium specimens were selected. The carcinoma cases included 3 pure AdenoCAs (enteric type, non-urachal), 3 pure keratinizing SCCs, and 3 conventional UroCAs. The normal urothelium specimens were selected from cystectomies with no prior history or evidence of UroCA. RNA was extracted, and the level of miRNA expression was determined for each sample using an 806 human miRNA code set with the nCounter miRNA Expression Assay (NanoString, Seattle, WA).
Results: Total RNA was extracted for all 12 cases. Of the 806 unique human miRNAs in the assay expression code set, 763 were expressed in all 12 samples. Individual miRNA expression among the 3 tumor groups (AdenoCA, SCC, and UroCA) differed, and miRNAs showing significant mean expression differences are listed in Table 1 (adjusted p<0.10).