To investigate the effectiveness of cytokines as pathological and prognostic markers for lung cancer.

Peripheral levels of cytokines and lung cancer related tumor markers during multiple hospitalization, as well as clinical data, including pathological type, survival time, clinical stage and age, were collected in a retrospective cohort with 127 lung cancer patients, 11 asthma and 68 pneumonia patients. All patients were admitted to Renji hospital, Shanghai Jiao Tong University School of Medicine. To identify new markers for lung cancer diagnostics, levels of cytokines were compared between lung cancer, asthma and pneumonia patients with statistical tests. The dynamics of significant cytokines were further evaluated among disease stages and during disease progression.

The cytokine IL-6 levels were significantly higher in lung cancer compared to that in asthma and pneumonia patients (P<0.001). However, the level of other cytokines were not statistically different among these three groups. Furthur analysis showed that IL-6 levels were related to pathological type with highest level in squamous lung cancer. IL-6 levels were also associated with TNM stage, and were higher in Ⅲ-Ⅳ stages (P<0.05). It was significantly increased with disease progression in patients who died of lung cancer (P<0.01). For individuals with high levels of IL-6, poorer overall survival was observed compared to those with lower levels of this cytokine (hazard ratio=3.04, P<0.05).

Peripheral IL-6 level is an effective marker for lung cancer progression and prognostic analysis.