Such novel molecularly defined epithelial renal tumors include succinate dehydrogenase (SDH)–deficient RCC, FH-deficient RCC, TFE3-rearranged RCC, TFEB-altered RCC, ALK-rearranged RCC, SMARCB1-deficient medullary RCC, and ELOC-mutated RCC. The gene discussed is TFE3; the disease is renal cell carcinoma.