Abstract 5342: Somatic bi-allelic loss of TSC genes in eosinophilic solid and cystic renal cell carcinoma (ESC RCC)

Abstract

Abstract Renal cell carcinoma (RCC) subtypes with overlapping histomorphologic features pose diagnostic challenges. For instance, a unique category of sporadic renal tumors with eosinophilic cytoplasm and solid and cystic growth pattern (ESC RCC) may mimic a RCC subtype usually encountered in patients with germline aberrations of tuberous sclerosis complex (TSC) genes (TSC RCC). Here, we used next-generation sequencing (NGS) technology to interrogate the clinicopathologic and molecular profiles of ESC RCC tumors. Mutational and copy number analysis of NGS data from ESC RCC tumors revealed a somatic bi-allelic loss of TSC family genes, specifically TSC1 or TSC2, in six out of seven profiled cases. However, the corresponding background kidney showed only wild type alleles, thus excluding any germline involvement and differentiating ESC RCC from TSC RCC. Furthermore, bi-allelic loss of the TSC genes occurred in a mutually exclusively manner in this cohort. Our study clarifies the molecular identity of ESC RCC, and can thus guide future therapeutic strategies and provide a basis for the revision of current RCC classification. Citation Format: Nicole D. Lee, Pankaj Vats, Xuhong Cao, Fengyun Su, Robert Lonigro, Kumpati Premkumar, Kiril Trpkov, Jesse K. McKenney, Rohit Mehra, Saravana M. Dhanasekaran, Arul M. Chinnaiyan. Somatic bi-allelic loss of TSC genes in eosinophilic solid and cystic renal cell carcinoma (ESC RCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5342.