Proteomic analysis of malignant and benign endometrium according to obesity and insulin-resistance status using Reverse Phase Protein Array

Obesity and hyperinsulinemia are known risk factors for endometrial cancer, yet thebiological pathways underlying this relationship are incompletely understood. Thisstudy investigated protein expression in endometrial cancer and benign tissue andits correlation with obesity and insulin resistance.One hundred and seven women undergoing hysterectomy for endometrial canceror benign conditions provided a fasting blood sample and endometrial tissue. Weperformed proteomic expression according to body mass index, insulin resistance,and serum marker levels. We used linear regression and independentttest for statis-tical analysis. Proteomic data from 560 endometrial cancer cases from The CancerGenome Atlas (TCGA) databank were used to assess reproducibility of results.One hundred and twenty seven proteins were significantly differentially expressedbetween 66 cancer and 26 benign patients. Protein expression involved in cellcycle progression, impacting cytoskeletal dynamics (PAK1) and cell survival (Rab25), were most significantly altered. Obese women with cancer had increasedPRAS40_pT246; a downstream marker of increased PI3K-AKT signaling. Obesewomen without cancer had increased mitogenic and antiapoptotic signaling byway of upregulation of Mcl-1, DUSP4, and Insulin Receptor-b.This exploratory study identified a number of candidate proteins specific to endo-metrioid endometrial cancer and benign endometrial tissues. Obesity and insulinresistance in women with benign endometrium leads to specific upregulation ofproteins involved in insulin and driver oncogenic signaling pathways such as thePI3K-AKT-mTOR and growth factor signaling pathways which are mitogenic andalso disruptive to metabolism. (Translational Research 2020; 000:1 16)