Management of Metastatic Renal Cell Carcinoma with Variant Histologies

Variant histology renal cell carcinoma (vRCC) encompasses rare non-clear cell subtypes that have long been associated with poor prognosis and minimal response to therapies targeting vascular endothelial growth factor and its receptor. Molecular advances have helped classify vRCC into distinct entities and identify putative targetable driver alterations, such as MET in papillary subtypes. More have since been identified in other vRCC subtypes, including alterations of tumor metabolism, chromatin remodeling genes, cell-cycle genes, and inactivation of tumor suppressors such as TP53 or NF2. New targeted therapies, as well as immune checkpoint inhibitors, have been in development and yielded encouraging results. Collaborative clinical trials will be an essential step toward better implementation of these regimens in clinical practice.