Serum Interleukin-6 Level and the rs1800795 Polymorphism in its Gene Associated with Neuroblastoma Risk in Chinese Children

BACKGROUND: The pro-inflammatory cytokine, interleukin-6 (IL-6), stimulates the metastasis of several neoplasms. An association of its serum level and the single nucleotide polymorphism (SNP) rs1800795 with neuroblastoma (NB) has been reported in American and Italian cohorts. This study was to clarify whether the same association exists in Chinese children. METHODS: A total of 130 NB patients, with 77 boys (59%), 53 girls (41%), mean age 41 ± 5 months, were assigned to two groups: high risk (HR) versus intermediate-low risk (non-HR), and 50 healthy children were randomly selected as the age- and gender-matched controls. Peripheral blood samples were analyzed to determine serum IL-6 level using enzyme linked immunosorbent assay and rs1800795 SNPs phenotype using polymerase chain reaction and gene sequencing. RESULTS: There were 87 NB patients in the HR group and 43 NB patients in the non-HR group. A comparison of allele and genotype frequencies of the rs1800795 polymorphism between patients and controls found no association with NB risk (P > 0.05). The frequency of GG+GC genotype was higher in HR-NB patients than in non-HR-NB patients (64.4% vs. 48.8%, P = 0.02), and serum IL-6 level was much higher in HR-NB patients with GG+GC genotype than in HR-NB patients with CC genotype (4.36 ± 1.1 pg/ml vs. 1.83 ± 0.5 pg/ml; P = 0.02), but not in Non-HR-NB patients. CONCLUSIONS: The polymorphism rs1800795 is associated with serum IL-6 level and level of NB risk. GG genotype might indicate that the tumor is highly malignant (prone to metastasis) and associated with poor prognosis.