GDNF and nonpapillary renal cell carcinoma: Kaplan-Meier survival curves (Figure 4A) show that patients with lower expression levels of 7 genes including BARX2, C2orf40, C4orf49, CYS1, GDNF, HLA-G and OTOA have better overall survival prognoses than those with higher expression levels of these 7 genes in ccRCC.