Microbiome-Mediated Modulation of the Tumour Immune Microenvironment in Oesophageal Squamous Cell Carcinoma

Oesophageal squamous cell carcinoma (ESCC) is the most prevalent type of oesophageal cancer. It is an aggressive malignancy with a poor prognosis, and recent studies have revealed the critical role of the microbiota in its occurrence and development. In this review, the current understanding of the impact of microbiota is summarized on the tumour immune microenvironment (TIME) in ESCC, focusing on intratumoural microbes and the oral-gut microbiota axis as potential therapeutic targets. The mechanisms are discussed by which specific bacterial species, such as Fusobacterium nucleatum (F. nucleatum), Porphyromonas gingivalis (P. gingivalis), Streptococcus spp., and Lactobacillus spp., influence immune responses and contribute to the progression of ESCC. Additionally, the potential of the microbiota is highlighted as a biomarker for early detection, prognosis, and prediction of treatment responses, and explore emerging strategies in microbiota-based immunotherapy that exploit the tumour-targeting properties of bacteria to improve cancer treatment outcomes. Despite these promising developments, the complex interactions between the microbiota and the immune system remain unclarified, and translating research findings into clinical practice is a significant challenge. In this review, the current advancements and emphasise the need for further investigation is summarized into the mechanisms of microbiota-mediated immunotherapy, while outlining future directions for developing personalised treatments for ESCC.