Background: Increasing evidence points to the urinary microbiota as a possible key susceptibility factor for early-stage bladder cancer (BCa) progression. However, the interpretation of its underlying mechanism is often insufficient, given that various environmental conditions have affected the composition of urinary microbiota. Herein, we sought to rule out confounding factors and clarify how urinary Eubacterium sp. CAG:581 promoted non-muscle invasive bladder cancer (NMIBC) development. Methods: Differentially abundant urinary microbiota of 51 NMIBC patients and 47 healthy controls (as Cohort 1) were first determined by metagenomics analysis. Then, we modeled the coculture of NMIBC organoids with candidate urinary Eubacterium sp. CAG:581 in anaerobic conditions and explored differentially expressed genes of these NMIBC tissues by RNA-Seq. Furthermore, we dissected the mechanisms involved into Eubacterium sp. CAG:581 by inducing extracellular matrix protein 1 (ECM1) and matrix metalloproteinase 9 (MMP9) upregulation. Finally, we used multivariate Cox modeling to investigate the clinical relevance of urinary Eubacterium sp. CAG:581 16S ribosomal RNA (16SrRNA) levels to the prognosis of 406 NMIBC patients (as Cohort 2). Results: Eubacterium sp. CAG:581 infection accelerated the proliferation of NMIBC organoids (p < 0.01); ECM1 and MMP9 were the most upregulated genes induced by the increased colony forming units (CFU) gradient of Eubacterium sp. CAG:581 infection via phosphorylating ERK1/2 in NMIBC organoids of Cohort 1. Excluding the favorable impact of potential contributing factors, the ROC curve of Cohort 2 manifested its 3-year AUC value as 0.79 and the cut-off point of Eubacterium sp. CAG:581 16SrRNA as 10.3 (delta CT value). Conclusion: Our evidence suggests that urinary Eubacterium sp. CAG:581 promoted NMIBC progression through the ECM1/MMP9 pathway, which may serve as the promising noninvasive diagnostic biomarker for NMIBC.

Intestinal Fusobacterium nucleatum (F. nucleatum) infection has been implicated into the progression of colorectal cancer (CRC). However, F. nucleatum as a biomarker in 5-fluorouracil (5-FU) resistance of CRC has not been fully analyzed by comparing with other types of gut microbiota. In order to further reduce the random error and bias of individual research, this meta‑analysis aimed to compare the diagnostic performance of intestinal Fusobacterium nucleatum, Bacteroides fragilis and Escherichia coli in 5-FU resistance to colorectal cancer and provide evidence‑based data to clinical practice. Comprehensive searches of PubMed, Embase, Cochrane Library and Web of Science databases were conducted. A total of 11 studies were selected according to the preestablished inclusion and exclusion criteria and analyzed by Review Manager 5.4 software, which included mapping of forest plots, heterogeneity tests, meta‑regression, sensitivity analysis and publication bias. Overall sensitivity and specificity of F. nucleatum detection in 5-FU resistance of CRC were 0.65 (95% CI:0.60-0.69) and 0.70 (95% CI:0.59-0.87), respectively. Its positive likelihood ratio (PLR) and negative likelihood ratio (NLR) in detecting colorectal cancer were 2.57 (95% CI:1.47-3.21) and 0.52 (95% CI:0.43-0.63). The diagnostic odds ratio (DOR) was 4.92 (95% CI:2.23-7.33), which significantly exceeds the performance of B. fragilis (DOR: 0.53, 95% CI:0.31-0.82) and E. coli (DOR: 0.63, 95% CI: 0.57-0.76) for indicating 5-FU resistance of CRC. Compared with intestinal B. fragilis and intestinal E. coli, intestinal F. nucleatum is more reflective of 5-FU resistance to colorectal cancer.