Molecular profiling of infiltrating urothelial carcinoma of the bladder.
311 Background: Infiltrating urothelial carcinoma (UC) is the most common variant of urinary bladder cancer. The prognosis for muscle infiltrating or metastatic UC of the bladder is poor with no major advances made in the last 20 years. We investigated a large cohort of such patients for specific genetic/biomarker alterations and compared them to other, less common urothelial malignancies. Methods: We reviewed 602 cases; 518 cases (86%) were locally advanced or metastatic UCs of the bladder and the remaining 84 cases (14%) were non-bladder UCs. Multiple methodologies for optimal assessment of biomarker expression (Caris Molecular Intelligence, Caris Life Sciences, Phoenix, AZ) were employed: Mutation analysis (Next-generation sequencing, Sanger, pyrosequencing, qPCR, RFLP), in-situ hybridization (fluorescent and chromogenic), immunohistochemistry, and RNA fragment analysis. Results: Bladder UC showed slightly higher rates of HER2/neu gene amplification (12% in bladder vs. 6% non-bladder, p=0.32) and EGFR ...