SLC31A1 and nonpapillary renal cell carcinoma: The expression of the copper importer (SLC31A1) and all the positive regulators of cuproptosis (FDX1, LIAS, LIPT1, DLD, DLAT, PDHA1, and PDHB) was significantly downregulated in the ccRCC samples compared with the normal renal samples (Figure 1B).