Fig. 2

Calculation of steady state concentrations of kynurenine and serotonin. A simplified scheme of tryptophan metabolism (including network location of kynurenine and serotonin) is depicted in the middle. All depicted kynurenine and serotonin concentrations were calculated by integrating gene expression data into a model of mammalian tryptophan metabolism [19]. a, b Calculated steady state concentrations of kynurenine (a) and serotonin (b) for models of ten different tissues [23]. Bar height equals mean, error resembles standard error of the mean (SEM), three replicates per tissue. c, d Calculated steady state concentrations of kynurenine (c) and serotonin (d) for models derived by intergration of expression data from five different cancer types (data downloaded from the cancer genome atlas TCGA). Asterisks show statistically significant differences in comparison to acute myeloid leukemia. (BRCA: Breast invasive carcinoma, n=805; OV: Ovarian serous cystadenocarcinoma, n=228; PRAD: Prostate adenocarcinoma, N=441; COAD: Colon adenocarcinoma, n=421; LAML: Acute myeloid leukemia, n=51; Box plots represent median and the 75% and 25% percentiles. Whiskers extend to the most extreme data point which is no more than 1.5 times the interquartile range from the box. Outliers are omitted for the sake of visibility)