title: Vascular endothelial growth factor pathway in endometriosis: genetic variants and plasma biomarkers.
abstract: OBJECTIVE
  To study single nucleotide polymorphisms (SNPs) involved in angiogenesis (VEGF, PLGF, VEGFR1, VEGFR2, HIF-1α) and plasma levels of the corresponding proteins (VEGF, PLGF, sVEGFR1, sVEGFR2) in women with and without endometriosis.
  
  
  METHODS
  Allele frequencies of vascular endothelial growth factor (VEGF) pathway SNPs and plasma levels of the corresponding proteins were investigated in patients with endometriosis and in controls.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Samples of DNA from 1,931 Caucasian patients were included (1,109 patients with endometriosis and 822 controls). An additional study group included 973 DNA samples from volunteers, self-reported to be healthy without laparoscopic evaluation.
  
  
  METHODS
  Women who underwent a laparoscopy for subfertility and/or pain and healthy volunteers without laparoscopic evaluation.
  
  
  METHODS
  Functional SNPs of the VEGF, VEGFR1, VEGFR2, HIF-1α genes and Hap Map tagging SNPs of the PLGF gene were genotyped by using iPLEX technology on a Sequenom MassArray and TaqMan SNP Genotyping Assay. The VEGF levels were determined in ethylenediaminetetraacetic acid plasma samples by using Bio-Plex Protein Array System. PLGF, sVEGFR1, and sVEGFR2 levels were measured in ethylenediaminetetraacetic acid plasma samples by using ELISA Quantikine kits.
  
  
  RESULTS
  A significant association was found between the rs2268613 polymorphism in the PLGF gene and PLGF plasma levels. In all study subjects, women with the AA variant of the rs2268613 PLGF gene had significantly lower PLGF plasma levels (median [interquartile range] 9.36 [8.19-10.43] pg/mL) than those with the AG variant (12.1 [11.81-20.84] pg/mL; P(a)=.0085, P(b)=.04), both before and after multiple testing. Plasma levels of VEGF were elevated in endometriosis patients (especially in minimal-mild endometriosis during the menstrual cycle phase) compared with laparoscopic controls but had a moderate diagnostic performance (area under the curve, 0.73) in this discovery dataset. At a cut-off plasma level of VEGF >3.88 pg/mL, minimal-mild stages of endometriosis were diagnosed with a sensitivity of 74% and a specificity of 80% during the menstrual phase of cycle. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing.
  
  
  CONCLUSIONS
  Genetic variants in the PLGF rs2268613 gene may influence plasma levels of the corresponding protein. Plasma levels of VEGF were elevated in endometriosis patients compared with controls. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing.
authors.affiliation: Department of Laboratory Medicine, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Vodolazkaia
authors.affiliation: Vesalius Research Centrum, VIB, Leuven, Belgium; Vesalius Research Center, Department of Oncology, KU Leuven, Leuven, Belgium.
authors.forename: Betul Tuba
authors.initials: BT
authors.lastname: Yesilyurt
authors.affiliation: Department of Medical Lab Sciences, Institute of Tropical Medicine and Infectious Diseases, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
authors.forename: Cleophas Mutinda
authors.initials: CM
authors.lastname: Kyama
authors.affiliation: Department of Obstetrics and Gynecology, Semmelweis University of Medicine, Budapest, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Bokor
authors.affiliation: Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: Schols
authors.affiliation: Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
authors.forename: Dana
authors.initials: D
authors.lastname: Huskens
authors.affiliation: Leuven University Fertility Center, Department of Obstetrics and Gynecology, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Christel
authors.initials: C
authors.lastname: Meuleman
authors.affiliation: Leuven University Fertility Center, Department of Obstetrics and Gynecology, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Karen
authors.initials: K
authors.lastname: Peeraer
authors.affiliation: Leuven University Fertility Center, Department of Obstetrics and Gynecology, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Carla
authors.initials: C
authors.lastname: Tomassetti
authors.affiliation: Department of Laboratory Medicine, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Xavier
authors.initials: X
authors.lastname: Bossuyt
authors.affiliation: Vesalius Research Centrum, VIB, Leuven, Belgium; Vesalius Research Center, Department of Oncology, KU Leuven, Leuven, Belgium.
authors.forename: Diether
authors.initials: D
authors.lastname: Lambrechts
authors.affiliation: Leuven University Fertility Center, Department of Obstetrics and Gynecology, University Hospital Gasthuisberg, Leuven, Belgium; Experimental Gynecology Laboratory, Department of Development and Regeneration, Organ System, KU Leuven, Leuven, Belgium; Division of Reproductive Biology, Institute of Primate Research, Nairobi, Kenya.
authors.forename: Thomas
authors.initials: T
authors.lastname: D'Hooghe
authors.affiliation: Experimental Gynecology Laboratory, Department of Development and Regeneration, Organ System, KU Leuven, Leuven, Belgium. Electronic address: amelie.fassbender@uzleuven.be.
authors.forename: Amelie
authors.initials: A
authors.lastname: Fassbender
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D004715:Endometriosis / Q000097:blood* / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000097:blood* / Q000235:genetics*
chemical_list: D015415:Biomarkers; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A
keywords: Endometriosis; VEGF pathway; plasma biomarkers; single-nucleotide polymorphism