title: Glioblastoma and ABO blood groups: further evidence of an association between the distribution of blood group antigens and brain tumours.
abstract: BACKGROUND
  Glioblastoma is a highly malignant brain tumour that usually leads to death. Several studies have reported a link between the distribution of ABO blood group antigens and a risk of developing specific types of cancer, although no consensus has been reached. This study aims to investigate the relationship between the distribution of ABO blood group antigens and the incidence of glioblastoma.
  
  
  METHODS
  The study cohort consisted of 115 glioblastoma patients who were diagnosed at King Abdullah University Hospital, Jordan, between 2004 and 2015. Three different patient populations made up three control groups and these were selected from among patients at the same institution between 2014 and 2015 as follows: 3,847 healthy blood donors, 654 accidental trauma patients admitted to the Departments of Neurosurgery and Orthopaedics, and 230 age- and sex-matched control subjects recruited blindly from the Departments of Paediatrics and Internal Medicine.
  
  
  RESULTS
  There was a significant association between the distribution of ABO blood group antigens and the incidence of glioblastoma. Post hoc residual analysis revealed that individuals with group A had a higher than expected chance of developing glioblastoma, while individuals with group O had a lower than expected chance. Furthermore, individuals with group A were found to be at a 1.62- to 2.28-fold increased risk of developing glioblastoma compared to individuals with group O.
  
  
  CONCLUSIONS
  In the present study, we demonstrate that, in Jordan, individuals with group A have an increased risk of developing glioblastoma, while individuals with group O have a reduced risk. These findings suggest that the distribution of ABO blood group antigens is associated with a risk of brain tumours and may play an important role in their development. However, further clinical and experimental investigations are required to confirm this association.
authors.affiliation: Department of Anatomy, Department of Neuroscience, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Mohammed Z
authors.initials: MZ
authors.lastname: Allouh
authors.affiliation: Division of Neurosurgery, Department of Neuroscience, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Mohammed M
authors.initials: MM
authors.lastname: Al Barbarawi
authors.affiliation: Division of Neurosurgery, Department of Neuroscience, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Mohammad Y
authors.initials: MY
authors.lastname: Hiasat
authors.affiliation: Department of Anatomy, Department of Neuroscience, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Al-Qaralleh
authors.affiliation: Department of Anatomy, Department of Neuroscience, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Emad I
authors.initials: EI
authors.lastname: Ababneh
mesh_terms: D000017:ABO Blood-Group System / Q000032:analysis*; D000328:Adult; D000367:Age Factors; D000368:Aged; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000209:etiology* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D005909:Glioblastoma / Q000209:etiology* / Q000473:pathology; D006801:Humans; D015994:Incidence; D007597:Jordan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D000017:ABO Blood-Group System