Gut Microbiota Dysbiosis and Colorectal Carcinogenesis: A Histopathological Study

Abstract

Gut microbiota dysbiosis is increasingly recognized as a critical factor influencing colorectal carcinogenesis, yet the mechanistic relationship between microbial imbalance and tissue-level pathological alterations remains incompletely understood. This study investigates the correlation between dysbiosis and colorectal tumor development by integrating high-throughput 16S rRNA microbial profiling with detailed histopathological examination of colorectal tissue samples. A mixed-methods experimental approach was employed, allowing quantitative microbial abundance, diversity indices, and dysbiosis scores to be analyzed alongside qualitative assessments of epithelial dysplasia, architectural distortion, inflammatory infiltration, and tumor grading. Results revealed significant enrichment of pro-carcinogenic taxa, particularly Fusobacterium nucleatum, mucin-degrading species, and inflammation-associated bacteria, in samples exhibiting advanced tumor grades. Diversity analyses demonstrated a marked decline in protective commensals, including butyrate-producing organisms, suggesting ecological collapse within the gut microbiome as lesions progressed. Statistical modeling further confirmed that higher dysbiosis scores strongly correlated with increased histopathological severity, supporting a dose-dependent microbial influence on neoplastic transformation. The integration of molecular and morphological findings provides robust evidence that dysbiosis contributes both to the initiation and progression of colorectal cancer. These findings highlight the potential of microbial signatures as early diagnostic biomarkers and emphasize the importance of microbiome-targeted strategies in risk prediction, prevention, and personalized therapeutic intervention.