A risk score using serum levels of 6 candidate markers (MIF, LGALS1, PPIB, CTSD, CUTA, GPI) distinguished ccRCC from non-RCC with an AUC of 0.86 (90% confidence interval: 0.77–0.95) and 0.88 (90% confidence interval: 0.78–0.98) with 5-fold cross validation in the training and test datasets, respectively (Figure 1F). Here, MIF is linked to nonpapillary renal cell carcinoma.