Objective To investigate the differential metabolites of lymph node metastasis in pancreatic ductal carcinoma (PDAC) and provide new ideas for the pathogenesis, early diagnosis and treatment of metastatic pancreatic cancer.

Methods Forty serum specimens of patients with pancreatic ductal carcinoma were collected and divided into lymph node metastasis group (18 cases) and non-metastasis group (22 cases). Thirty-one serum specimens were also collected from the healthy control group. Liquid chromatographytandem mass spectrometry was used to analyze the differential metabolites and metabolic pathways between patients with PDAC and healthy controls as well as between lymph node metastasis and non-metastasis groups.

Results Principal component analysis and partial least squares-discriminant analysis revealed statistically significant differences in metabolites and metabolic pathways between patients with PDAC and the healthy controls and between lymph node metastasis and non-metastasis groups. The differences in profiles were also statistically significant. Seventy-six different metabolites and 11 metabolic pathways were screened between patients with PDAC and the healthy controls, among which phenylalanine metabolism and histidine metabolism were the two most influential metabolic pathways. Four different metabolites were screened between lymph node metastasis and non-metastasis groups, and the expression of ethopropazine and phenylalanine were upregulated but the expression of tetrahydrodeoxycorticosterone and oxprenolol were downregulated.

Conclusion Metabolites are significantly altered in the lymph node metastasis group of patients with PDAC compared with the non-metastasis group. Ethopropazine, phenylalanine, tetrahydrodeoxy corticosterone, and oxprenolol are potential biomarkers of lymph node metastasis in patients with PDAC.