Functional links between the microbiome and the molecular pathways of colorectal carcinogenesis

Colorectal cancer (CRC) is a common cancer, with a concerning rise in early-onset CRC cases, signalling a shift in disease epidemiology. Whilst our understanding of the molecular underpinnings of CRC has expanded, the complexities underlying its initiation remain elusive, with emerging evidence implicating the microbiome in CRC pathogenesis. This review synthesizes current knowledge on the intricate interplay between the microbiome, tumour microenvironment (TME), and molecular pathways driving CRC carcinogenesis. Recent studies have reported how the microbiome may modulate the TME and tumour immune responses, consequently influencing cancer progression, and whilst specific bacteria have been linked with CRC, the underlying mechanisms remains poorly understood. By elucidating the functional links between microbial landscapes and carcinogenesis pathways, this review offers insights into how bacteria orchestrate diverse pathways of CRC development, shedding light on potential therapeutic targets and personalized intervention strategies.