Systematic verification of saliva-based biosignatures for oral cancer via targeted metabolomics.

Oral squamous cell carcinoma (OSCC) remains a major global health challenge, and early detection is essential for improving patient outcomes. To identify reliable salivary biomarkers, we performed a targeted metabolomics study using 13C2/12C2-dansylation, integrating candidate metabolites from published OSCC metabolomics datasets and systematically verifying them through LC-MRM-MS. A panel of 26 metabolites was quantified in saliva samples from 299 subjects, including healthy controls (n = 98), oral potentially malignant disorders (OPMD I, n = 50; OPMD II, n = 53), and OSCC patients (n = 98). Among these, cadaverine, N-acetylcadaverine, choline, glycine, and tryptophan were significantly dysregulated across disease groups. Cadaverine, N-acetylcadaverine and choline were consistently elevated in OSCC and showed progressive increases with disease stages, whereas glycine levels declined. A four-metabolite panel (cadaverine, N-acetylcadaverine, choline, glycine) demonstrated strong diagnostic performance in distinguishing OSCC from healthy controls (AUC = 0.91). Correlation analyses further revealed coordinated regulation among polyamine-related metabolites, suggesting a reprogramming of ornithine-polyamine metabolism in OSCC progression. In conclusion, we establish a verified salivary metabolite panel with high discriminatory power for OSCC detection. These findings highlight polyamine-associated metabolic alterations as a hallmark of malignant transformation in the oral cavity and support salivary metabolomics as a clinically accessible tool for non-invasive screening and risk stratification.