Interleukin-6 -634G>C genetic polymorphism is associated with prognosis following surgery for advanced thoracic esophageal squamous cell carcinoma.

OBJECTIVE

Systemic and/or local interleukin-6 (IL-6) reportedly plays an active role in the progression and prognosis of thoracic esophageal squamous cell carcinoma (TESCC). We assessed the associations between IL-6 and IL-6 receptor (IL-6R) genetic polymorphisms, tumoral IL-6 expression and survival rates following surgery.

METHODS

The study participants were 63 Japanese patients treated between 2003 and 2008 for T2-T4 advanced TESCC using curative esophagectomy without neoadjuvant treatment. We investigated IL-6 -634G>C (rs1800796) and IL-6R 48892A>C (rs8192284, Asp358Ala) genetic polymorphisms using DNA from peripheral blood samples. In addition, tumoral IL-6 expression was investigated immunohistochemically in resected specimens, and serum IL-6 was measured using a human IL-6 immunoassay.

RESULTS

There was a significant difference in survival between patients with the IL-6 -634G/G+G/C genotype and those with the C/C genotype, such that their 5-year overall survival rates were 42 and 72%, respectively. By contrast, the IL-6R 48892A /C genotype and tumoral IL-6 expression had no significant effect on survival among patients. Univariate and multivariate analyses revealed that IL-6 -634G>C polymorphism was an independent prognostic factor with a hazard ratio of 3.

CONCLUSIONS

IL-6 -634G>C genetic polymorphism may be a predictive prognostic factor in patients receiving esophagectomy for TESCC.