Cytokine gene polymorphisms in gastric cancer patients from two Italian areas at high and low cancer prevalence

Polymorphisms of interleukin-1β (IL-1β), IL-1 receptor antagonist (IL1-RN), and tumor necrosis factor-α (TNF-α) genes are supposed to be key determinants of gastric cancer risk. Our aim was to study the association between these polymorphisms and gastric cancer in two areas characterized by high (Pavia/Bologna, North Italy) and low (San Giovanni Rotondo, South Italy) gastric cancer prevalence. Genomic DNA was obtained from 216 healthy donors and 98 gastric cancer patients from Pavia and Bologna, and 146 healthy donors and 86 gastric cancer patients from San Giovanni Rotondo. Two SNP in IL-1β (−511 C/T) and TNF-α (−308 G/A) as well as the VNTR polymorphism of IL-1RN locus were studied. A significant linkage disequilibrium was found between IL-1β −511 and IL-1RN. Genotype and allele frequencies at the IL-1β, IL-1RN, and TNF-α loci in gastric cancer cases were not significantly different from controls. An epistatic effect between IL-1β −511 and IL-1RN was found with the IL-1β −511C/IL-1RN*2 haplotype conferring a significant protection against the intestinal-type of gastric cancer in the Southern population. In conclusion, IL-1β, IL1-RN, and TNF-α genotypes are not associated with gastric cancer in Italian patients. An epistatic interrelationship between IL-1β −511 and IL-1RN confers protection against gastric cancer in low-risk Italian population.