FH and Unclassified Renal Cell Carcinoma: As germline and somatic mutations of FH have been described in hereditary leiomyomatosis RCC (HLRCC) and a small number of sporadic type II pRCC6, 16, 40, we performed 2SC (2-succino-cystein) and FH immunohistochemistry to investigate the recurrent FH somatic mutations observed in three of our uRCC cases (Fig. 1a).