Fig. 2

Comprehensive serum metabolomic profiling reveals significantly up-regulated kynurenine in response to nivolumab treatment. a Volcano plots showing average serum metabolite (n = 106, represented as points) level changes after 4 weeks of nivolumab treatment compared to baseline in CA209-038 melanoma patients. b Histogram showing the changes of kynurenine/tryptophan (Kyn/Trp) ratios 4 weeks after nivolumab treatment compared to baseline in melanoma patients. c Volcano plot showing average serum metabolite (n = 106) changes between week 6 and week 4 after nivolumab treatment in melanoma patients. d Volcano plots showing average serum metabolite (n = 202) level changes after 4 weeks of nivolumab treatment compared to baseline in CheckMate 025 RCC patients. e Histogram showing the changes of Kyn/Trp ratios 4 weeks after nivolumab treatment compared to baseline in CheckMate 025 RCC patients. f Volcano plot showing average serum metabolite (n = 202) level changes after 4 weeks of everolimus treatment compared to baseline in CheckMate 025 RCC patients. g Pearson correlation analysis between Kyn/Trp ratios and PD-L1/IDO1/TDO mRNA expression at week 4, prior anti-CTLA4 treatment (ipilimumab), and tumor mutation load in melanoma patients. The q values in a, c, d, f were calculated based on paired t-tests for all profiled metabolites with Benjamini-Hochberg multiple testing corrections