Comprehensive molecular characterization and analysis of muscle-invasive urothelial carcinomas.

4500Background: We reported the integrated molecular analysis of 131 tumors in 2014 (Nature 507:315, 2014) and now report on the entire cohort of 412 tumors from the TCGA project in chemotherapy-naive, muscle-invasive urothelial bladder cancer. Methods: Following strict clinical and pathologic quality control, tumors were analyzed for DNA copy number variants, somatic mutations (WES), DNA methylation, mRNA, non-coding RNA (lncRNA and miRNA) and (phospho-) protein expression, gene fusions, viral integration, pathway perturbation, clinical correlates, outcomes, and histopathology. Results: There was a high overall somatic mutation rate (8.2/Mb), as previously reported. There were 58 significantly mutated genes (SMGs) (MutSig_2CV), increased from 32 in the original report. We identified 5 mutation signatures including APOBEC-a and b, ERCC2, C > T_CpG, and a single ultra-mutated sample with a functional POLE mutation. APOBEC mutagenesis explained 70% of the mutation burden and was associated with survival (p ...