Serum Untargeted Metabolomics Profiling of Esophageal Squamous Cell Carcinoma in High-Incidence Areas of China

Background: As a frequent malignant tumor arising in the upper gastrointestinal tract, esophageal squamous cell carcinoma (ESCC) exhibits an exceptionally high prevalence in China. Metabolic reprogramming is a hallmark of cancer, and serum metabolites have been implicated in the development of various gastrointestinal cancers. However, their role in ESCC remains to be further elucidated. Objective: The present research sought to characterize the differences in serum metabolism between patients with ESCC and healthy controls (HCs), and explore their potential roles in ESCC initiation. Methods: From September 2023 to September 2024, 70 previously untreated ESCC patients and 72 matched HCs were recruited. Serum untargeted metabolomics was analyzed by ultra‑high performance liquid chromatography‑Orbitrap‑tandem mass spectrometry (UHPLC‑Orbitrap‑MS/MS), followed by bioinformatic analysis. Results: Compared with HCs, 713 differentially expressed metabolites were identified in ESCC patients, with lipids and lipid‑like molecules representing the biggest category (16.1%). Enrichment analysis of metabolic pathways indicated that biosynthesis of unsaturated fatty acids (UFAs) was the most significantly dysregulated pathway ( P < 0.001), involving a total of seven key metabolites: cis-11-eicosenoic acid, cis-11,14-eicosadienoic acid, docosapentaenoic acid, erucic acid, linoleic acid, oleic acid, and palmitic acid. All seven metabolites were significantly elevated in both early‑stage (Stage I–II) and locally advanced (Stage III) ESCC patients versus HCs, with no significant differences between the two patient groups. A diagnostic signature derived from these metabolites displayed an area under the curve (AUC) of 0.804 (95% confidence interval: 0.729– 0.880). Conclusion: This study demonstrates significant serum metabolic alterations in ESCC patients, particularly in lipid metabolism and UFA biosynthesis. The seven‑metabolite panel shows favorable discriminatory performance for ESCC, suggesting their potential as biomarkers. Keywords: esophageal squamous cell carcinoma, untargeted metabolomics, serum metabolites, biosynthesis of unsaturated fatty acid, biomarkers