Figure 2. Comparison of the CRC microbial signature to IBD microbiomes.

1. Ranked predictions of the metagenomic classifier (mean test prediction for study populations F, G and H) are plotted for each individual (labels on top indicate grouping) with the percentage of positive CRC predictions annotated in red. Proportions of true negatives (TN), false positives (FP), false negatives (FN), and true positives (TP) are shown at the bottom for a decision boundary of 0.275 (see Fig 1). Application of the CRC classifier to metagenomes from ulcerative colitis (UC) and Crohn's disease (CD) patients indicates a threefold increased false-positive rate for inflammatory bowel disease (IBD) patients, suggesting some similarities between CRC and IBD.
2. Relative abundance distributions of the four most discriminative markers for CRC classification (see Fig 1A) are plotted for each patient subgroup, including UC and CD (see key). All markers showed significantly stronger association with (enrichment in) CRC than with IBD (Wilcoxon test, UC and CD tested together; see also Supplementary Fig S8). Boxplots are as defined in Fig 1E.