The Microbiome-Arginine-Immune Axis in Oral Squamous Cell Carcinoma: Metabolic Competition and Therapeutic Opportunities

Oral squamous cell carcinoma (OSCC) is strongly influenced by metabolic and immune dysregulation. Recent evidence highlights the role of L-arginine metabolism and arginase isoforms (ARG1/ARG2) in tumour progression, immune suppression, and metabolic reprogramming. This narrative review integrates published evidence with an independent bioinformatic reanalysis of publicly available transcriptomic and immune infiltration datasets to examine arginase signalling in oral squamous cell carcinoma and to explore how oral dysbiosis may contribute to extracellular arginine depletion and tumour-promoting immune dysfunction. These findings support the microbiome-arginine-immune axis as a promising framework for future biomarker development and metabolism-based therapeutic strategies in OSCC.