SOX2 and nonpapillary renal cell carcinoma: We first used IHC to detect AR, YBX1 and SOX2 protein level in 30 ccRCC patient samples, and the results indicated that AR expression is higher in normal tissues compared to tumor tissues and adjacent tumor tissues, while YBX1 and SOX2 expression is higher in tumor tissues and adjacent tumor tissues compared to normal tissues (Fig. 6A) which is consistent with TCGA database (Additional file 1: Fig. S4A).