Urine Proteomics Study Of Ovarian Endometriosis

BackgroundEndometriosis is a common gynecologic disorder and due to a lack of non-invasive detection methods,it can take up to 12 years before an affected woman obtains a diagnosis and receives appropriate treatment.Therefore,the identification of a specific biomarker that can be detected quickly and non-invasively is urgently needed.In this study,the urine proteome,a potentially rich source of biomarkers,is examined in patients with or without endometriosis in an attempt to identify novel protein biomarkers that can be used to diagnose endometriosis.MethodsThis study was designed as a prospective pilot study.Ninety-seven patients who underwent surgery for an adnexal mass or unexplained infertility were enrolled in this study based on their final diagnoses.They were divided into endometriosis(n=25,Group U)and three control groups.In the control group,25 patients had benign ovarian cysts(Group B),25 had unexplained infertile(Group A)and 22 had ovarian carcinomas(Group C).Five randomly selected samples from each group were individually labeled with TMT 6-plex and analyzed by LC-MS/MS.All of the differentially expressed urinary proteins were used for bioinforrmatics analysis.A total 77 samples were analyzed and 265 peptides from 131 proteins were verified using PRM.Receiver operating characteristic(ROC)curve analysis was performed for each candidate biomarker.ResultsWhen comparing Groups U and A,127 differential proteins were identified(fold change>1.4,P<0.05),with 99 up-regulated and 28 down-regulated.When comparing Groups B and A,37 differential proteins were identified in Group B,while when comparing Groups C and A,142 differential proteins were identified in Group C.Moreover,81 significant proteins were specially identified in Group U.IPA analysis revealed that certain canonical pathways,including the high mobility group box 1(HMGB1),CD40,and lymphotoxin p receptor(LT?R)signaling pathways,are significantly activated in Group U.These proteins were associated with biological functions such as cellular infection,DNA binding and epithelial cell line migration.Collectively,190 peptides(105 proteins)were found to be consistent with the TMT results.Of these,Group U had 32 differentially expressed peptides(29 up-regulated and 3 down-regulated)that correspond to 25 proteins.The AUC values of 18 peptides(16 proteins)were over 0.75.With a cutoff of 14.2,the ROC analysis indicated that histone 4(H4)has a high diagnostic potential for endometriosis(AUC=0.848),with a sensitivity of 70%and specificity of 80%.A combination ROC analysis showed that a panel of four proteins(H4,RPN1,ARF3,and MYH10)provides the largest area under the curve value(AUC=0.863).ConclusionThis is the first application of a TMT-PRM approach to identify and validate endometriosis associated urine biomarkers.The findings presented herein are consistent with the hypothesis that endometriosis is a chronic inflammatory disease with an immunological assoeiation.HW may serve as a potential disease biomarker or therapeutie target for endometriosis.To our knowledge,this is the first study to observe an elevated histone level in body fluids obtained from endometriosis patients.Of the identified potential biomarkers,the combination of H4,RPN1,ARF3,and MYH10 show the greatest diagnostic value.While this study provides a good foundation,further studies are required to further validate the results presented.