Gastric cancer (GC) is the second cause of cancer-related death worldwide. Interleukin (IL)-16 has a vital role in the development and homeostasis of the immune system. In the present study, we evaluated an exon variant rs4072111 C/T polymorphism and 3' UTR variant rs1131445 C/T within the miRNA binding with gastric cancer susceptibility in Iranian population. Genomic DNA was isolated from peripheral blood samples according to phenol chloroform extraction. The genotypes of IL-16 polymorphisms rs1131445 T/C and rs4072111 T/C were determined by polymerase chain reaction-restriction fragment length polymorphism method. In this case control study, a total of 256 patients with gastric cancer (238 cases (92.9 %) non-cardia and 18 cases (7.1 %) cardia) and 300 healthy control subjects were evaluated. In the present study, we found a significant association between rs4072111 of IL-16 gene and risk of GC in Iranian population. Individuals with CT genotype showed a significant association with 1.79-fold increased risk of GC (P = 0.008; adjusted OR 1.792; 95 % CI 1.164-2.759). The significant association was also detected for T allele of rs4072111 and increased risk of GC (P < 0.001; adjusted OR 1.981; 95 % CI 1.354-2.900). We also observed statistically a significant relationship between rs1131445 of IL-16 CT genotype and GC risk. Carriers of IL-16 CT genotype compared with TT genotype had 1.44 times higher increased likelihood of GC (P = 0.048; adjusted OR 1.445; 95 % CI 1.003-2.084). After stratification according to gender, we observed that in rs1131445, CT and CC male carriers had a higher risk of GC than females (P = 0.08; adjusted OR 1.608; 95 % CI 0.945-2.737 and P = 0.08; adjusted OR 2.186; 95 % CI 0.897-5.325, respectively). We also observed that for male carriers with C allele in rs1131445, there was a 1.53-fold higher risk of GC risk than female subjects (P = 0.029; adjusted OR 1.53; 95 % CI 1.04.4-2.248). We found that the rs1131445 T/C and rs4072111 T/C variants of IL-16 were significantly associated with increased risk of GC in Iranian population.
Keywords: Gastric cancer; IL-16; Polymorphism.