Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 6 3 2014 06 27 36 42 EN Kourosh Ghanadi Department of Internal Medicine, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran Khatereh Anbari Department of Social Medicine, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran Zia Obeidavi Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran Behrouz Beiranvand Kermanshah University of Medical Sciences, Kermanshah, Iran Mohammad Almasian Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran Omid Beiki Kermanshah University of Medical Sciences, Kermanshah, Iran AND Department of Clinical Neuroscience, Karolinska Institutet, Sweden 2014 12 15 2014 12 15 Background: The objective of the present study is to investigate the relationship between the familial history of digestive system cancers and development of gastric cancer. Methods: In this case-control study conducted in 2012, 84 patients with a definite diagnosis of gastric cancer, diagnosed using endoscopy and pathological study of biopsies, were compared with 84 people with the same age and sex as the control group. The control group consisted of outpatients referring to the dermatology and ophthalmology clinics. All patients having a chronic condition were excluded from the control group. All patients filled out a questionnaire to determine whether they had any first-degree relatives with upper or lower digestive tract cancers. Data were analyzed using the Fisher’s exact and logistic regression tests. Results: The mean age of the patients was 65.4±10.7 and 64.3 percent of the patients were male. A statistically significant relationship between a background of gastric or colon cancer among first-degree relatives and the development of gastric cancer was observed An estimation of the odds ratio of the development of gastric cancer among patients with first-degree relatives who had developed gastric or colon cancers to the control group was 4.5 (95% CI=2.21-8.16) and 5.5 (95% CI=2.11-10.71), respectively. No significant relationship was found between a background of esophageal cancer among first-degree relatives and the development of gastric cancer among the participants (P_value = 0.24). Conclusion: The presence of relationships between the development of gastric cancer and a familial background of digestive tract cancers need to be studied in further research and with larger samples. https://bccr.tums.ac.ir/index.php/bccrj/article/view/149 https://bccr.tums.ac.ir/index.php/bccrj/article/download/149/pdf