We found that the expression level of GDF15 in tumor samples, compared to that in normal samples, was significantly decreased in kidney malignancies, including chromophobe renal cell carcinoma (KICH), clear-cell renal cell carcinoma (KIRC), and papillary renal cell carcinoma (KIRP) (Fig. 1A). Here, GDF15 is linked to papillary renal cell carcinoma.