Molecular signaling and the role of targeted therapies in bladder cancer.

Through our growing understanding of the molecular mechanisms that drive urothelial transformation and the growth, invasion and metastasis of bladder cancer, we are able to identify an increasingly broad spectrum of molecules and pathways that are suitable for novel targeted therapies. At the same time we are armed with an increasing number of agents designed to disrupt these signaling pathways, and, as these enter the clinical arena in other cancers, the barriers to use in bladder cancer patients decline. Targeted therapy for bladder cancer, however, remains in its infancy, and no major breakthroughs have been achieved. Here we review some of the molecular targets that have been best characterized in bladder cancer, as well as some of the newer targets that appear most promising. We will review the experience up to this point in testing targeted agents against these pathways, and describe some novel agents that have yet to be tested in clinical trials but have shown significant potential in pre-clinical models.