Clinical Utility of Chromosome Genomic Array Testing for Unclassified and Advanced-Stage Renal Cell Carcinomas

Context.— Cytogenomic analysis provides a useful adjunct to traditional pathology in the categorization of renal cell carcinomas (RCCs), particularly in morphologically ambiguous cases, but it has disadvantages, including cost. Objective.— To define the clinical scenarios in which this technology has direct clinical applications. Design.— DNA was isolated from paraffin-embedded tissue from 40 selected cases of RCC. Chromosome genomic array testing was performed using the OncoScan. Results.— Of 23 cases of unclassified renal tumors, 19 (83%) were reclassified with incorporation of cytogenetic and histologic features, including 10 as clear cell RCC, 2 as collecting duct carcinoma, 2 as papillary RCC, and 1 as novel TFEB-amplified tumor lacking TFEB translocation. Of 5 tumors with “hybrid” oncocytic features, 3 were reclassified as an eosinophilic variant of chromophobe RCC and 1 as oncocytoma. Appropriate staging in 2 patients was determined by identifying distinct, nonshared cytogenetic profiles. Of 11 cas...