title: Hereditary risk factors for the development of gastric cancer in younger patients.
abstract: BACKGROUND
  It is believed that the development of gastric cancer (GC) before the age of 50 has a hereditary basis. Blood group A and history of gastric cancer in first-degree relatives have been shown to be risk factors for GC.
  
  
  METHODS
  In this case-control study, we enrolled patients with GC who were diagnosed before the age of 50. Patients who were diagnosed as having GC were selected. A total of 534 cases were found; of these, 44 diagnosed before the age of 50 were included in the case group. For the control group, 22 males and 22 females were randomly selected from the remaining subjects, who had diagnoses of GC after the age of 50. All the surviving patients and family members of the dead patients were interviewed about the history of cancer in the family and the age at which other family members developed cancer. The blood group of each subject was also obtained.
  
  
  RESULTS
  forty-four cases under 50 years old (mean age: 36.2 years) and forty-four controls (mean age: 67.1 years) were enrolled in the study. At the time of the study, 59.1% of the study group and 50% of the control group were alive (P value = NS). In the study group, 68.1%, 13.6%, 13.6% and 4.5% had blood groups O, A, B and AB, respectively. In the control group the corresponding figures were 27.7%, 63.6%, 6.8% and 4.5%. First or second-degree relatives with cancer, including gastric (the most frequent), breast, lung, gynecological and hematological malignancies, were noted in 54.5% of the cases and 11.4% of the controls (p < 0.01). Family histories of cancer were accepted as valid provided that they were based on valid medical documents.
  
  
  CONCLUSIONS
  It seems that the development of GC before the age of 50 is likely to be accompanied by familial susceptibility. Interestingly, our study showed a significant correlation between blood group O and the development of gastric cancer under the age of 50.
authors.affiliation: Digestive Disease Research Center, Tehran University of Medical Sciences, Shariati Hospital, Kargar Shomali St, Tehran 14114, Iran. yaghoobi@ams.ac.ir
authors.forename: Mohammad
authors.initials: M
authors.lastname: Yaghoobi
authors.forename: Naser
authors.initials: N
authors.lastname: Rakhshani
authors.forename: Farhad
authors.initials: F
authors.lastname: Sadr
authors.forename: Raheleh
authors.initials: R
authors.lastname: Bijarchi
authors.forename: Yasamin
authors.initials: Y
authors.lastname: Joshaghani
authors.forename: Ashraf
authors.initials: A
authors.lastname: Mohammadkhani
authors.forename: Arezou
authors.initials: A
authors.lastname: Attari
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Akbari
authors.forename: Mahshid
authors.initials: M
authors.lastname: Hormazdi
authors.forename: Reza
authors.initials: R
authors.lastname: Malekzadeh
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000235:genetics*
chemical_list: D000017:ABO Blood-Group System