Molecular subtype classification of urothelial bladder cancer and its clinical relevance

Current advances in molecular techniques and bioinformatics allowed the analysis of complex molecular patterns in various cancers including muscle-invasive bladder cancer. As a consequence, in the last few years numerous gene- and protein expression-based molecular classifications have been recommended. Recently a comprehensive consensus classification for muscle-invasive urothelial bladder cancer has been published, distinguishing 6 subgroups with a potential impact on clinical decision-making. At the same time, the therapeutic landscape of muscle-invasive bladder cancer becomes increasingly differentiated as novel checkpoint inhibitors have been available for cisplatin-ineligible and/or resistant patients. Furthermore, promising results have been obtained with FGFR targeting agents. Therefore, molecular subtyping will probably have a crucial role in individualized therapeutic decision-making in bladder cancer. In the present work, we summarize the evolution, recent advances and potential therapeutic relevance of molecular subclassifications in bladder cancer.