PREX2 and nonpapillary renal cell carcinoma: In the training phase, the expression levels of emRNAs were detected in an additional cohort of 142 clinical samples, including localized ccRCCs (n = 92) and healthy controls (n = 50), by RT–qPCR, which revealed that CUL9, KMT2D, PBRM1, PREX2, and SETD2 were significantly higher in the ccRCC group than in the healthy group, and each of the candidate biomarkers achieved good performance for distinguishing localized ccRCCs from healthy controls with corresponding AUCs of 0.611, 0.668, 0.639, 0.742, and 0.680, respectively (Table 2, Fig. 1A, and Additional file 1: Fig. S3A).