NRN1 and nonpapillary renal cell carcinoma: Based on the TCGA PanCancer Atlas RNA-seq dataset of ccRCC cohort, we extracted 1,974 and 3,265 genes co-expressed with NRN1 and CXCR4, respectively, with Spearmen’s correlation coefficient ≥0.2 and determined 941 common genes as the overlap of genes co-expressed with both NRN1 and CXCR4 (Supplementary Figure 4).