Background and objective: Interleukin (IL)-10 is a pleiotropic cytokine that can both stimulate and suppress the immune response. Previous studies have reported that IL-10 production was significantly elevated in cachectic patients, and it has been confirmed that polymorphisms of the IL10 gene could influence its expression. Therefore, we designed this study to investigate whether polymorphisms of the IL10 gene were associated with cachexia in patients with low-third gastric cancer in a Chinese population.
Methods: 190 patients with low-third gastric cancer were included in this study. The serum levels of IL-10 were measured by radioimmunoassay. The single nucleotide polymorphisms (SNPs) at positions -1082A/G, -819T/C, and -592A/C in the IL10 gene promoter were analyzed using polymerase chain reaction (PCR) restriction fragment length polymorphism (PCR-RFLP).
Results: The serum levels of IL-10 were significantly higher in patients with cachexia than in those without (Z = -10.66, p < 0.001). Single SNP analysis showed that the frequency of the IL10 -1082G allele was increased in patients with cachexia (p = 0.02). The -1082AG and -819CC genotypes were observed to be associated with an increased risk of cachexia. In a logistic regression analysis adjusted for actual weight and carcinoma stage, the -1082AG genotype was associated with an odds ratio (OR) of 2.45 (95% CI 1.21, 4.96; p = 0.01), and the -819CC genotype was associated with an OR of 3.70 (95% CI 1.20, 11.39; p = 0.02) for cachexia. Furthermore, haplotype analysis of the -1082A/G, -819T/C, and -592A/C SNPs revealed that at least five haplotypes (ATA, ACC, GCC, ACA, and ATC) were present in this Chinese population, and the -1082G/-819C/-592C (GCC) haplotype was associated with a significantly increased risk of cachexia as compared with the ATA haplotype (OR = 2.42; 95% CI 1.17, 5.00; p = 0.02).
Conclusion: Our results indicate that genetic polymorphisms of IL-10 may influence susceptibility to cachexia in patients with low-third gastric cancer in this Chinese population.