This study aims to compare alterations in the proteomes of human epithelial ovarian cancer xenografts between the stressed and non-stressed immunodeficient mice.Also,to explore the molecular mechanisms linking chronic psychological stress to ovarian cancer oncogenesis and progression.Methods:SK-OV-3 cells were injected subcutaneously into nude mice.The stress group was subjected to a chronic physical restraint protocol for 6 h on 35 consecutive days,while the control group was unrestrained.All mice were sacrificed on Day 36 after SK-OV-3 cell injection,and tumors were excised.Tumor tissues were processed for 2D gel electrophoresis,mass spectrometry (nanoUPLC-ESI-MS/MS) and western blotting.Results:The expression of twenty proteins was found to be significantly altered between the stress and control groups,of which fourteen were up-regulated,five were down-regulated,and one protein was found only in the stress group.All proteins were identified by UPLC-ESI-MS/MS,and western blotting results were consistent with those of proteomic methods.Conclusions:The present results provide new evidence relating to the molecular mechanism underlying the relationship between psychological stress and tumor progression.