Proteomic Profiling of Endometrial Cancer Tissues Reveals Differential Expression of Proteomes in Obese Versus Non-Obese Patients

Endometrial cancer (EC) is the leading gynecological malignancy worldwide. Obesity is reported to be associated with 50% of EC cases. Significant gaps remain in investigating specific molecular mechanisms behind the obesity-driven EC. Women diagnosed with EC undergoing total hysterectomy were recruited. Patients were divided into two groups: EC-obese with BMI > 29.9 kg/m² (n = 10) and EC-Non-obese with BMI ≤ 29.9 kg/m² (n = 10). Tumor tissues were subjected to label-free quantitative proteomic analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Differentially expressed proteins were identified and subjected to pathway enrichment and network analyses to characterize obesity-associated alterations. Proteomic profiling showed a significant dysregulation of 456 proteins: 171 upregulated and 285 downregulated. Proteins involved in endoplasmic reticulum quality control particularly endoplasmic reticulum lectin 1 (ERLEC1), were reduced. Conversely, EC-obese demonstrated upregulation of hepatocyte growth factor (HGF), integrin-linked kinase (ILK), CTTNBP2 N-terminal-like protein (CTTNBP2NL), and lysyl oxidase homolog 1 (LOXL1), implicating activation of inflammatory pathways. Bioinformatic analysis showed downregulation of immune-related pathways, including neutrophil degranulation, complement activation in the EC-obese group. ROC analysis identified apolipoprotein(a), phospholipase B-like 1, CTTNBP2NL, and ILK as significant proteins that can differentiate between the obese and non-obese states. Our findings provide insights into obesity-associated proteomic changes in EC and highlight candidate proteins that can be used for molecular stratification after further validation.