Alteration of fecal tryptophan metabolism correlates with shifted microbiota and may be involved in pathogenesis of colorectal cancer

Figure 5 Correlations between differential bacteria at the genus level using linear discriminant analysis effect size analysis and fecal metabolites. The heatmap presents the Spearman correlation coefficients between fecal metabolites and genera with significantly different relative abundance in the colorectal cancer (CRC) patients and healthy controls (HCs). Indoles were positively related to the genera Asaccharobacter (Actinobacteria) and Parabacteroides (Bacteroidetes), and members of the phylum Firmicutes (such as Clostridium XlVb, Fusicatenibacter, Anaerofilum, and Anaerostipes), whose relative abundances were lower in CRC patients than in HCs in the linear discriminant analysis effect size analysis. ^aP < 0.05, ^bP < 0.01. HC: Healthy control; CRC: Colorectal cancer. IPA: Indole-3-propionic acid; IAA: Indole-3-acid-acetic; KYN: Kynurenine; Trp: Tryptophan.