This analysis suggested that the differentially abundant metabolites in the SDEL group were all associated with central carbon metabolism in cancer, ABC transporters, arginine biosynthesis, tyrosine, alanine, aspartate and glutamate metabolism as well as renal cell carcinoma pathways (P < 0.01, frequency-distance relationship correction; Figure 4D). This evidence concerns the gene ABCG2 and renal cell carcinoma.