LAUSR

617Background: Metabolic disruption is frequent in renal cell carcinoma (RCC). Loss of the mitochondrial fumarate hydratase (FH) enzyme is associated with enhanced glycolytic metabolism, angiogenesis and clinical aggressiveness in type 2 papillary RCC. However, FH expression has never been evaluated in clear cell RCC (ccRCC). In this study, we investigated the impact of FH expression on the outcomes of patients (pts) with metastatic ccRCC (mccRCC). Methods: We included pts with mccRCC, for whom formalin-fixed, paraffin embedded (FFPE) tissue from the primary tumor had been obtained before initiation of systemic treatment. FH levels were evaluated by immunohistochemistry (IHC), and were defined as “normal” if FH expression in most cancer cells was comparable to the adjacent normal tubular cells and “low” in the opposite case. We evaluated the association between FH levels and clinico-pathological characteristics through the chi-squared or Fisher’s exact test. The log-rank test was used to compare survival ...