[Serum level and genotype of interleukin-6 in patients with esophageal cancer]

Abstract

Objective: To investigate the polymorphism of the interleukin-6 (IL-6) gene promoter-572C/G and -634C/G in patients with esophageal cancer, and to study the relation between the serum level and genotype of interleukin-6 and esophageal cancer.

Methods: Peripheral blood samples were collected from 118 patients with esophageal cancer and 130 healthy persons as controls. The polymorphism of IL-6 was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The serum level of IL-6 was determined by enzyme-linked immunosorbent assay (ELISA).

Results: The frequency of the genotype GG of the IL-6 (-634) site in the cancer group was 12.7%, significantly higher that that of the control group (3.8%, P<0.05). The risk of esophageal cancer of the G allele carriers was 1.759 times that of the C allele carriers (OR=1.759, 95% CI=1.150-2.691). The serum level of IL-6 of the esophageal cancer group was (16.9+/-5.3) ng/L, significantly higher than that of the control group [(4.6+/-2.6) ng/L, P<0.01]. The serum level of IL-6 of the esophageal cancer with the G allele carriers was (18.8+/-6.1) ng/L, significantly higher than that of the esophageal cancer without the G allele carriers [(13.2+/-6.0) ng/L, P<0.01]. There was no significant difference in the distribution of the IL-6 gene-572C/G polymorphism between the 2 groups (P>0.05).

Conclusion: IL-6 gene-634C/G polymorphism is associated with the esophageal cancer. The IL-6 allele G carriers may be at increased risk of the esophageal cancer because of the increase of the IL-6 expression.