title: Ki-67 expression in hydatidiform moles and hydropic abortions.
abstract: BACKGROUND
  Differential diagnosis of hydatidiform moles from non-molar specimens as well as their sub-classification such as complete and partial hydatidiform moles are important for clinical management and accurate risk assessment for persistent gestational trophoblastic disease, but diagnosis based solely on histomorphology suffers from poor interobserver and intraobserver reproducibility.
  
  
  OBJECTIVE
  This study was undertaken to determine whether the expression of Ki-67 protein could differentiate these entities.
  
  
  METHODS
  We performed Ki-67 immunohistochemical staining in 19 molar (8 partial and 11 complete moles) and 10 non-molar (hydropic abortions) formalin-fixed, paraffin-embedded tissue samples. Ploidy analysis using flow cytometry had confirmed diploidy in hydropic abortions and complete moles and triploidy in partial moles.
  
  
  RESULTS
  Ki-67 immunoreactivity was assessed in villous cytotrophoblasts, syncytiotrophoblasts and stromal cells. Positive cells were found to be restricted mostly to the villous cytotrophoblasts, while syncytiotrophoblasts showed an absence of immunostaining for Ki-67, and occasional weak nuclear staining was seen in the stromal cells. There was a significant difference in Ki-67 immunoreactivity of cytotrophoblastic cells between hydropic abortions and complete moles (P < 0.001), hydropic abortions and partial moles (P = 0.002) and also between complete and partial moles (P < 0.001). On the other hand, there is significant overlap in the Ki-67 immunoreactivity between complete and partial moles (++ staining category) and between partial moles and hydropic abortions (+ staining category).
  
  
  CONCLUSIONS
  Despite the significant differences , Ki-67 immunostaining could not be helpful in distinguishing molar placentas from hydropic abortions as well as partial from complete hydatidiform moles, because there are considerable overlaps between results in different categories.
authors.affiliation: Department of Pathology, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Khooei
authors.affiliation: Department of Anatomical Sciences, Urmia University of Medical Sciences, Urmia, IR Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Atabaki Pasdar
authors.affiliation: Department of Anatomy and Cell Biology, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Fazel
authors.affiliation: Immunology Research Center, Bu Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Mahmoudi
authors.affiliation: Department of Anatomy and Cell Biology, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Nikravesh
authors.affiliation: Department of Medical Ethics, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Khaje Delui
authors.affiliation: Department of Anatomical Sciences, Urmia University of Medical Sciences, Urmia, IR Iran.
authors.forename: Bagher
authors.initials: B
authors.lastname: Pourheydar
keywords: Abortion; Hydatidiform Mole; Immunohistochemistry; Ki-67 Antigen