title: ABO blood group and cancer.
abstract: BACKGROUND
  ABO blood type has been associated with various malignancies, including pancreatic cancer. Our aim was to study this association using data from a hospital-based tumour registry.
  
  
  METHODS
  From the tumour registry, we retrieved data from 15,359 cancer patients treated during 2000-2003 at the European Institute of Oncology (Milan, Italy), with defined ABO blood type. We performed a case-control analysis, comparing the distribution of ABO blood types of patients with each specific form of cancer against that of patients with other forms of cancer. We also reviewed the literature and performed a meta-analysis on the association between ABO blood group and pancreatic cancer.
  
  
  RESULTS
  We observed a significantly lower frequency of blood type O in patients with exocrine pancreatic cancer compared to patients with other forms of cancer (29% versus 44%; P<0.001; odds ratio (OR), 0.53; 95% confidence intervals (CI), 0.33-0.83). This association was confirmed by the meta-analysis of seven prior studies (summary relative risk, 0.79; 95% CI, 0.70-0.90). No association was found for endocrine pancreatic cancer or for cancer originating in other organs.
  
  
  CONCLUSIONS
  Our data suggest that the association between ABO blood group and cancer is limited to exocrine pancreas malignancy.
authors.affiliation: Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy. simona.iodice@ieo.it
authors.forename: Simona
authors.initials: S
authors.lastname: Iodice
authors.forename: Patrick
authors.initials: P
authors.lastname: Maisonneuve
authors.forename: Edoardo
authors.initials: E
authors.lastname: Botteri
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Sandri
authors.forename: Albert B
authors.initials: AB
authors.lastname: Lowenfels
mesh_terms: D000017:ABO Blood-Group System / Q000097:blood*; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood*; D010190:Pancreatic Neoplasms / Q000097:blood; D012307:Risk Factors
chemical_list: D000017:ABO Blood-Group System