Interleukin-1beta gene (IL-1B) and interleukin 1 receptor antagonist gene (IL-1RN) polymorphisms and gastric cancer risk in an Omani Arab population.
BACKGROUND
Gastric cancer (GC) is the most common malignancy in Oman. Interleukin-1beta gene (IL-1B) and interleukin-1 receptor antagonist gene (IL-1RN) polymorphisms have been associated with increased GC risk. No previous studies have examined their role in an Arab population. We tested the associations between polymorphisms of IL1B at positions -31, -511, and +3954 and the IL-1RN polymorphism [variable number of tandem repeats (VNTR) and TC polymorphism at the -2018 position] and GC in Omani Arab patients.


METHODS
Genomic DNA was extracted from peripheral blood of 245 control subjects and 118 gastric cancer patients. The DNA samples were analyzed using the TaqMan allelic discrimination test for IL-1B -31, -511, and +3954 polymorphisms and IL-1RN -2018 polymorphism. The VNTR of IL-1RN was genotyped using the polymerase chain reaction followed by agarose gel electrophoresis.


RESULTS
There was an association between the presence of IL-1RN*2 allele and gastric cancer [odds ratio (OR) = 2.2, 95% confidence interval (CI) = 1.0-3.3, P = 0.04). The GC risk further increased to OR = 3.5 (95% CI = 1.0-11.9) in Helicobacter pylori-positive patients. No association was found between any of the other polymorphisms studied and GC.


CONCLUSIONS
IL-1RN polymorphism increased the risk of GC in an Omani Arab population, consistent with previous reports. In contrast, the IL-1B -31 polymorphism was not associated with an increased GC risk. These findings underscore the role of cytokine gene polymorphisms in the development of GC and further support the ethnic differences in the effect of IL-1B polymorphism on GC carcinogenesis.
Al-Moundhri
Mansour S
MS
Medical Oncology Unit, Department of Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, PO Box 35, Muscat, 123, Oman.
Al-Nabhani
Mariam
M
Al-Bahrani
Bassim
B
Burney
Ikram A
IA
Al-Madhani
Ali
A
Ganguly
Shym S
SS
Al-Yahyaee
Said A
SA
Grant
Christopher S
CS
D000328:Adult; D018912:Arabs / Q000208:ethnology; D016022:Case-Control Studies; D004247:DNA / Q000097:blood / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D016481:Helicobacter Infections / Q000235:genetics / Q000382:microbiology; D016480:Helicobacter pylori / Q000472:pathogenicity; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000235:genetics*; D053583:Interleukin-1beta / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009850:Oman / Q000453:epidemiology; D011110:Polymorphism, Genetic / Q000235:genetics*; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000097:blood / Q000208:ethnology / Q000235:genetics* / Q000382:microbiology
D053590:Interleukin 1 Receptor Antagonist Protein; D053583:Interleukin-1beta; D004247:DNA