FH and nonpapillary renal cell carcinoma: High ribose metabolism gene expression was present in both ccRCC and CIMP-RCC, with CIMP-RCC showing the greatest expression, likely due to the increased production of NADPH counteracting the cellular stress induced by the loss of fumarate hydratase in these tumors (Ooi et al., 2011; Patra and Hay, 2014; Sourbier et al., 2014).