Tongue-coating microbiome as a predictor of solid tumors: an updated scoping review of clinical studies

This study explores the potential of tongue coating microbiota as a non-invasive biomarker for cancer and precancerous lesions by integrating insights from multi-omics technologies and Traditional Chinese Medicine (TCM) tongue diagnosis. By bridging modern molecular research with TCM diagnostic principles, this study systematically reviewed the relationship between tongue microbiota and oncological conditions, identifying 18 eligible studies through searches in PubMed, Embase, and Web of Science. The analysis reveals significant differences in microbial diversity, abundance, metabolic pathways, and functional characteristics, which enable the partial differentiation of cancer patients from healthy individuals. However, existing research remains constrained by limited sample sizes, inconsistent analytical approaches, and a lack of integrated multi-dimensional datasets. This review highlights the promising diagnostic potential of the tongue coating microbiota in cancer detection, while suggesting that future studies should focus on standardizing methodologies and employing integrated multi-omics approaches to elucidate underlying mechanisms and advance clinical applications.