title: Combined mRNA microarray and proteomic analysis of eutopic endometrium of women with and without endometriosis.
abstract: BACKGROUND
  An early semi-invasive diagnosis of endometriosis has the potential to allow early treatment and minimize disease progression but no such test is available at present. Our aim was to perform a combined mRNA microarray and proteomic analysis on the same eutopic endometrium sample obtained from patients with and without endometriosis.
  
  
  METHODS
  mRNA and protein fractions were extracted from 49 endometrial biopsies obtained from women with laparoscopically proven presence (n= 31) or absence (n= 18) of endometriosis during the early luteal (n= 27) or menstrual phase (n= 22) and analyzed using microarray and proteomic surface enhanced laser desorption ionization-time of flight mass spectrometry, respectively. Proteomic data were analyzed using a least squares-support vector machines (LS-SVM) model built on 70% (training set) and 30% of the samples (test set).
  
  
  RESULTS
  mRNA analysis of eutopic endometrium did not show any differentially expressed genes in women with endometriosis when compared with controls, regardless of endometriosis stage or cycle phase. mRNA was differentially expressed (P< 0.05) in women with (925 genes) and without endometriosis (1087 genes) during the menstrual phase when compared with the early luteal phase. Proteomic analysis based on five peptide peaks [2072 mass/charge (m/z); 2973 m/z; 3623 m/z; 3680 m/z and 21133 m/z] using an LS-SVM model applied on the luteal phase endometrium training set allowed the diagnosis of endometriosis (sensitivity, 91; 95% confidence interval (CI): 74-98; specificity, 80; 95% CI: 66-97 and positive predictive value, 87.9%; negative predictive value, 84.8%) in the test set.
  
  
  CONCLUSIONS
  mRNA expression of eutopic endometrium was comparable in women with and without endometriosis but different in menstrual endometrium when compared with luteal endometrium in women with endometriosis. Proteomic analysis of luteal phase endometrium allowed the diagnosis of endometriosis with high sensitivity and specificity in training and test sets. A potential limitation of our study is the fact that our control group included women with a normal pelvis as well as women with concurrent pelvic disease (e.g. fibroids, benign ovarian cysts, hydrosalpinges), which may have contributed to the comparable mRNA expression profile in the eutopic endometrium of women with endometriosis and controls.
authors.affiliation: Department of Obstetrics and Gynecology,  Leuven University Fertility Center, UZ Gasthuisberg, 3000 Leuven,  Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Fassbender
authors.forename: N
authors.initials: N
authors.lastname: Verbeeck
authors.forename: D
authors.initials: D
authors.lastname: Börnigen
authors.forename: C M
authors.initials: CM
authors.lastname: Kyama
authors.forename: A
authors.initials: A
authors.lastname: Bokor
authors.forename: A
authors.initials: A
authors.lastname: Vodolazkaia
authors.forename: K
authors.initials: K
authors.lastname: Peeraer
authors.forename: C
authors.initials: C
authors.lastname: Tomassetti
authors.forename: C
authors.initials: C
authors.lastname: Meuleman
authors.forename: O
authors.initials: O
authors.lastname: Gevaert
authors.forename: R
authors.initials: R
authors.lastname: Van de Plas
authors.forename: F
authors.initials: F
authors.lastname: Ojeda
authors.forename: B
authors.initials: B
authors.lastname: De Moor
authors.forename: Y
authors.initials: Y
authors.lastname: Moreau
authors.forename: E
authors.initials: E
authors.lastname: Waelkens
authors.forename: T M
authors.initials: TM
authors.lastname: D'Hooghe
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000737:chemistry; D014408:Biomarkers, Tumor / Q000378:metabolism; D001706:Biopsy; D016022:Case-Control Studies; D004715:Endometriosis / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology*; D004717:Endometrium / Q000473:pathology; D005260:Female; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010455:Peptides / Q000737:chemistry; D011237:Predictive Value of Tests; D040901:Proteomics / Q000379:methods*; D012333:RNA, Messenger / Q000378:metabolism*; D012189:Retrospective Studies; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D060388:Support Vector Machine
chemical_list: D015415:Biomarkers; D014408:Biomarkers, Tumor; D010455:Peptides; D012333:RNA, Messenger