The relationship between BIRC5 expression and outcome of ccRCC. BIRC5 expression and OS (a); BIRC5 expression and DFS (b); survival across the high- and low-risk group (the numbers below the horizontal axis represent the number of individuals not presenting the event of the corresponding risk group along time) (c); and BIRC5 expression across the high- and low-risk group (d). CI, concordance index; OS, overall survival; DFS, disease-free survival; ccRCC, clear-cell renal cell carcinoma.