FBP1 and nonpapillary renal cell carcinoma: Notably, Cdkn1a, which codes for the cell-cycle inhibitory protein p21, and Fbp1, which codes for fructose bisphosphatase-1 identified as a tumor suppressor in ccRCC (41), were specifically upregulated following Vhl inactivation in CDIC, but not PT cells (Supplementary Fig. S2C).