Label-free quantitative urinary proteomics for non-invasive biomarker discovery in endometrial cancer

Endometrial cancer (EC) is a growing global healthcare concern. The diagnosis of EC involves invasive techniques. There is a pressing need for reliable, non-invasive screening methods utilizing biomarkers that diagnose these patients.

We conducted a case-control study consists of 40 women including 20 EC (cancer group) and 20 controls (control group) recruited from King Khalid University Hospital, King Saud University. All participants include both cancer and control groups underwent histopathological examination for confirmation. Cancer group had a confirmed diagnosis of EC and control group confirmed benign tissue, verified by histopathological examination. Midstream urine samples were collected under standardized fasting conditions, and proteins extracted using methanol-chloroform precipitation. An untargeted label-free LC-MS/MS mass spectrometric approach combined with bioinformatics was used to determine changes in the proteomic profiles. Multivariate statistical analysis (PCA, OPLS-DA) using MetaboAnalyst v6.0. functional annotation and pathway enrichment were carried out using Ingenuity Pathway Analysis (IPA) and PANTHER classification to identify key biological processes and canonical pathways associated with EC.

The participants in this cohort were matched for age, with a mean of 59.50 ± 7.13 years in the EC group, and 54.15 ± 10.45 years, in the controls. The study found EC patients had significant differences in 193 proteins (117 upregulated and 76 downregulated) when compared to the controls. There was a clear separation seen between the EC and control groups in multivariate analyses using the PCA, PLS-DA, and OPLS-DA. Glutamate dehydrogenase 1 (GLUD1) and Iduronate 2-sulfatase, both of which were found to be downregulated, and histidine-rich glycoprotein, which was upregulated in EC patients with AUCs of 0.945, 0.965, and 0.875 in the receiver operating curve analysis. Pathway enrichment analysis and network analysis provided molecular insights into the activation of Fc gamma receptor-dependent phagocytosis, complement activation, TRIM21 signaling, and amino acid metabolism.

The study identified three key biomarkers, GLUD1, Iduronate 2-sulfatase, and histidine-rich glycoprotein, that were significantly dysregulated in patients with EC. The findings highlight that there are systemic immune engagement and tumor-driven metabolic shifts in EC.