Non‑targeted metabolomics reveals diagnostic biomarker in the plasma of patients with lung cancer

Lung cancers are malignant tumors with high incidence and mortality rates and a 5-year survival rate that depends on the stage at the time of diagnosis. Screening methods for lung cancer are becoming increasingly diverse, but existing approaches lack sensitivity or specificity for early lesions, posing notable challenges for the early diagnosis of lung cancer. Therefore, it is essential to explore potential biomarkers with high sensitivity and specificity to achieve early diagnosis. The present study employed liquid chromatography-mass spectrometry to analyze plasma metabolic changes in patients with lung cancer or pulmonary nodules and in healthy individuals. By combining quantitative and qualitative methods, differential metabolites were identified and the performance of these metabolites was evaluated using receiver operating characteristic curve analyses to screen for potential biomarkers. A total of 50 differential metabolites, six of which had an area under the curve of >0.9, were identified among the three groups and regarded as potential biomarkers for distinguishing between lung cancer, pulmonary nodules and healthy individuals, as well as between lung cancer and pulmonary nodules. In addition, metabolic pathways were screened using the Kyoto Encyclopedia of Genes and Genomes databases. The results demonstrated that significant changes were observed in the metabolism of substances including linoleic acid, α-linolenic acid, arginine and proline, suggesting that the development of lung cancer may be associated with alterations in amino acid and lipid metabolism. In conclusion, the present findings provided potential biomarkers to differentiate between lung cancer, pulmonary nodules and healthy individuals, offering insights into the pathological mechanisms of lung cancer.