Gut Bacteria as a Biomarker for Inflammation and Cancer: Insights from Clinical and Microbial Analysis

Growing evidence suggests that gut bacteria can influence inflammation and tumorigenesis, yet the specific microbial species involved remain unclear. To investigate the role of gut bacteria in inflammation-based tumorigenesis by identifying specific microbial species and functional profiles associated with health statuses (healthy, chronic inflammation/dysbiosis, and cancer), and to determine their correlations with clinical parameters and disease mechanisms. Here, we assessed clinical parameters and gut bacteria across three health statuses: 17 healthy individuals, 10 with chronic inflammation (dysbiosis), and 16 with cancer. The Gut Microbiota Health Index (GMHI) was significantly higher in healthy individuals, indicating that robust gut bacteria correlated with better health, while lower GMHI values in dysbiosis and cancer reflected microbial imbalances. Additionally, the Microbial Dysbiosis Index (MDI) was elevated in dysbiosis and cancer, supporting distinct microbial profiles for these conditions. Specific bacterial families emerged as potential biomarkers: increased Enterobacteriaceae and decreased beneficial Bifidobacteriaceae and Lactobacillaceae were noted in disease states. Correlation analyses identified a significant positive association between Lentisphaeria and clinical parameters in the dysbiosis group, while a strong link between Proteobacteria diversity and total bile acids was found in cancer, suggesting ties to inflammation. Random forest analysis revealed that dominant bacterial diversity significantly impacts health status, particularly concerning liver and kidney function disruptions. Connectivity analyses indicated that higher positive connectivity in dysbiosis and cancer groups was associated with less diverse, redundant bacterial communities. The novelty of our findings pioneers a staged, three-state comparison that quantitatively tracks microbiota trajectory from health through chronic inflammation to cancer, revealing that early depletion of Bifidobacteriaceae / Lactobacillaceae , elevated Enterobacteriaceae , and a shift toward high-connectivity, low-diversity networks precede and predict systemic organ dysfunction and malignant transformation. • Healthy individuals have robust and balance gut microbiota compare with disease. • Proteobacteria diversity can serve as a biomarker for predicting tumorigenesis. • Dominant bacterial diversity correlated with liver and kidney function. • Healthy individuals have higher bacterial connectivity than disease.