Fig. 4

Urine metabolome changes after tumor resection. a PLS-DA model showed metabolic discrimination after tumor resection in Component 1 (26.4%, p < 0.001) and Component 2 (21.6%, p < 0.01); b comparison of the relative abundance of metabolite classes between Before group and After group; c Z score plot and d volcanic plot of differentially expressed metabolites, a single dot represent a patient in Z score plot or a metabolite in volcanic plot; e pathway enrichment of differentially expressed metabolites; f carnitine, g acetylcarnitine, and h octanoylcarnitine levels remarkably dropped after tumor resection (paired t test p < 0.05; p < 0.05; p < 0.05). SCFAs: short chain fatty acids