Gut microbiota signatures in colorectal cancer: Evidence synthesis from umbrella review and probiotic intervention studies

Figure 1  Preferred reporting items for systematic reviews and meta-analyses flow diagram of the study selection process for the umbrella meta-analysis.

Figure 2  Preferred reporting items for systematic reviews and meta-analyses flow diagram of the study selection process for the probiotic/synbiotic intervention analysis.

Figure 3 Umbrella review analysis of gut microbiota genera associated with colorectal cancer. A: Consistency classification and reporting frequency of microbial genera (k); B: Median effect sizes of the genera reported in the meta-analyses. The error bars represent interquartile ranges, and the bubble size reflects the number of included meta-analyses.

Figure 4 Forest plot of the second-order meta-analysis for gut microbiota genera associated with colorectal cancer risk. Pooled effect sizes with 95% confidence intervals are shown for genera that were reported in at least two independent meta-analyses (k ≥ 2). Taxa are ordered by the magnitude of the effect size. The color intensity corresponds to the number of meta-analyses included for each genus.

Figure 5 Species-level taxonomic mapping of gut microbiota genera significantly associated with colorectal cancer (P ≤ 0. 05, k ≥ 5). A: Oral-derived genera; B: Gut-derived genera; C: Mixed-derived genera (oral and gut).

Figure 6 RoB2 risk of bias summary for the included intervention studies. A: Domain-level and overall RoB2 judgments for each study; B: Proportion of studies judged at each risk of bias level for each item, presented as percentages across all included studies.

Figure 7 Forest plots and leave-one-out sensitivity analyses of probiotic/synbiotic effects on the gut microbiota in colorectal cancer patients. Forest plots show pooled standardized mean differences with 95% confidence intervals. A: Forest plots of eligible quantitative meta-analyses by taxon; B: Leave-one-out sensitivity analysis. SMD: Standardized mean differences; CI: Confidence interval.

Figure 8 Individual-study standardized mean differences for microbial taxa reported in single intervention studies. Standardized mean differences with 95% confidence intervals are shown for taxa reported in single studies (k = 1). SMD: Standardized mean differences; CI: Confidence interval.

Figure 9 Qualitative summary of microbiota changes in the study of Park et al[26]. Red and blue indicate increased and decreased relative abundance, respectively. NS: Not significant.