Blocking immune checkpoints in prostate, kidney, and urothelial cancer: An overview.

Despite a long history of immunotherapeutic approaches to treatment, most genitourinary malignancies are not cured by existing immunotherapy regimens. More recently, cell surface molecules known as immune checkpoints have become the focus of efforts to develop more effective immunotherapies. Interactions between these molecules and their ligands inhibit the proliferation and function of tumor-specific lymphocytes. A monoclonal antibody blocking 1 of these checkpoints was approved for the treatment of metastatic melanoma and is now being tested in other malignancies. The objective responses seen in these early trials of checkpoint blockade are driving renewed enthusiasm for cancer immunotherapy. There are several ongoing and planned trials in genitourinary malignancies of single-agent inhibitors, as well as combinations targeting multiple checkpoints or adding other types of therapies to checkpoint blockade.