Metabolic and Oxylipin Signature of Testicular Germ Cell Tumors in Seminal Plasma

Testicular germ cell tumors (TGCTs) are the most common malignancy in young adult men, and the development of reliable non-invasive diagnostic tools remains a clinical priority. Seminal plasma is a complex yet accessible biofluid that reflects the function of the male reproductive system and may capture metabolic alterations associated with testicular pathology.

This study aimed to characterize the seminal plasma metabolome of TGCT patients using a multi-platform metabolomics strategy that covers polar metabolites and oxylipins.

Seminal plasma from 37 TGCT patients and 11 non-TGCT clinical controls was analyzed by capillary electrophoresis-mass spectrometry (CE-MS) and oxylipin profiling using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Immunohistochemical analysis of testicular tumor tissue was used to confirm enzymatic expression degree.

CE-MS revealed coordinated alterations in polar metabolites, particularly many involved in energy metabolism, suggesting a disruption of testicular metabolic homeostasis in TGCTs. Reduced levels of key energy-related amino acids in plasma suggested increased metabolic demand in tumor cells, consistent with altered biosynthetic and redox pathways. Additional changes in hexosamine pathway metabolites indicated potential alterations in protein glycosylation and secretory activity. Oxylipin profiling using targeted LC-MS/MS identified several lipid mediators with significant differences between groups. Four compounds (9,10-DiHOME, 6-trans-LTB₄, TXB₂, and 14,15-DiHETrE) were elevated in TGCT samples and demonstrated discriminatory potential in univariate analyses. A composite oxylipin ratio of these compounds achieved excellent diagnostic performance, indicating that oxylipin-based signatures may support TGCT detection. Immunohistochemical staining confirmed arachidonate 12-lipoxygenase (ALOX12) expression in tumor tissue, confirming biological plausibility for the observed oxylipin alterations.

Seminal plasma carries detectable metabolic signatures of TGCT, encompassing alterations in energy metabolism and inflammation-related lipid mediators. These findings establish a foundation for developing non-invasive metabolomic biomarkers for TGCT and warrant validation in larger and independent cohorts.