IL-8 expression predicts lung adenocarcinoma prognosis

By Lynda Williams, Senior medwireNews Reporter

Interleukin (IL)-8 expression is associated with a poor lung adenocarcinoma prognosis, say Japanese researchers, especially in patients whose tumours are positive for the KRAS mutation.

Expression of the angiogenic chemokine – which is known to be upregulated by the KRAS mutation – was measured in tumour samples taken from 136 patients with lung adenocarcinoma using quantitative reverse transcription polymerase chain reaction.

IL-8 expression was significantly higher in tumour specimens taken from patients with KRAS mutations than in patients with epidermal growth factor receptor (EGFR) mutations or in those with wild-type copies of both of the oncogenes.

Moreover, disease-free survival and overall survival were significantly shorter in patients with high IL-8 expression, defined as over 50% of tumour area stained for IL-8 in immunohistochemical analysis, than patients with lower levels of expression.

Both survival outcomes were also significantly shorter in patients whose adenocarcinoma was KRAS-positive and showed high IL-8 expression than in patients with tumours shown to have wild-type KRAS and low expression.

In multivariate analysis, higher IL-8 expression continued to be a significant predictor for both shorter disease-free and overall survival, with hazard ratios of 1.013 and 1.014, after adjusting for pathological stage.

IL-8 expression was also significantly higher in specimens taken from smokers than nonsmokers and in patients aged 70 years or older than in younger patients, report Noriaki Sunaga (Gunma University, Maebashi) and co-authors in the British Journal of Cancer.

But further analysis revealed age-related increase in IL-8 expression was only true for those who did not smoke and thus ageing may be the biggest cause of IL-8 expression increase in nonsmokers. This means age-related IL-8 expression increase is a potential cause of lung adenocarcinoma in nonsmokers, the researchers say.

“Our findings also raise the possibility that an anti-IL-8 therapeutic strategy could improve the clinical outcome in patients with oncogenic KRAS-driven lung adenocarcinoma”, the team concludes.

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