Alterations in the Gut Microbiota of Patients with Esophageal Squamous Cell Carcinoma: A Cross-Sectional Study Conducted in a High-Incidence Region of China.

Background: Esophageal squamous cell carcinoma (ESCC) is an aggressive and often fatal upper gastrointestinal cancer. Although the gut microbiota plays a critical role in the development of digestive tract malignancies, especially those in the lower gastrointestinal tract, clinical studies exploring its association with ESCC remain limited. Objective: This study aimed to delineate differences in gut microbiota diversity and composition between ESCC patients and healthy controls (HCs) through full-length 16S rRNA sequencing. Methods: Between September 2023 and September 2024, 171 fresh fecal samples were obtained from 93 patients with ESCC and 78 HCs in Hebei Province, China. Sequencing of the full-length 16S rRNA gene regions (V1-V9) was conducted using the PacBio Sequel II platform, followed by comprehensive bioinformatic analysis. Results: Relative to HCs, ESCC patients exhibited markedly lower alpha diversity and distinct beta diversity. At the genus level, enrichment of Bifidobacterium, Ligilactobacillus, Lactococcus, Intestinibacter, Paucibacter, Acinetobacter, and Mogibacterium was identified in the ESCC cohort. A diagnostic model incorporating these seven genera achieved an area under the curve (AUC) of 0.726 (95% confidence interval: 0.650-0.801). Additionally, these significantly different genera were associated with some clinicodemographic information. Furthermore, a decline in several short-chain fatty acid (SCFA)-producing genera, including Blautia, Anaerostipes, and the Eubacterium_hallii_group, was observed in ESCC patients. Bacterial phenotype predictions using BugBase and functional profiling with PICRUSt2 further demonstrated significant microbiota differences between patients and healthy subjects. Conclusion: Comprehensive analysis of the gut microbial community in ESCC patients from Hebei Province, China, revealed significant dysbiosis involving community structure, bacterial phenotypes, functional capacity, and metabolic pathways. These alterations may be potentially associated with the occurrence of ESCC.