Molecular and Genomic Profiling to Identify Actionable Targets in Chromophobe Renal Cell Cancer

Abstract

Metastatic chromophobe renal cell cancer (chRCC) is a rare subtype of RCC with no standard treatment. We performed molecular profiling of 12 chRCC cases to identify alterations predictive of response to therapy. Tests included immunohistochemistry assays, fluorescence in situ hybridization, and next-generation sequencing. Analysis identified c-KIT overexpression in 6/9 (67%) samples analyzed, and loss of protein expression of RRM1 and MGMT in 11/12 (92%) and of PTEN in 7/12 samples (58%). Mutations of TP53, PTEN, APC, and VHL genes were identified. In summary, molecular profiling of chRCC identified alterations in genes and protein expression that might provide a mechanistic rationale for off-label use of approved therapies in advanced chRCC, and could guide the design of molecularly targeted clinical trials. Patient summaryIn this study, we evaluated samples of a rare type of kidney cancer (chromophobe type) and identified potential genetic markers that could be used to individualize treatment and possibly improve treatment outcomes.