Salivary Cytokine Levels in Lung Cancer with Distant and Regional Metastases

Optimization of methods for diagnostics and prediction of lung cancer, which occupies a leading position in the structure of oncological diseases, still remains an important task. In this study we have investigated the level of cytokines and acute-phase proteins in saliva of patients with lung cancer in dependence on the tumor size, and distant and regional metastasis. The case-control study included 121 patients, which were divided into 3 groups: the main group (patients with diagnosed lung cancer, n = 70), the reference group (patients with non-malignant lung pathologies, n = 12) and the control group (conditionally healthy individuals, n = 39). All participants answered the questionnaire, underwent biochemical study of saliva and histological verification of the diagnosis. The content of IL-2 and IL-4 in saliva reduced in both lung cancer and inflammatory lung diseases, whereas the levels of IL-18, IL-8 and TNF-α decreasd in lung cancer and increased in non-malignant pathologies. Tumor progression was accompanied by an increase in the level of proinflammatory cytokines (IL-6, IL-8, IL-18, TNF-α), whereas the levels of IL-2, IL-4 and IL-10 decreased. Although saliva levels of C-reactive protein and tumor markers increased in lung cancer they did reach the level of statistical significance as compared with the reference group. Thus, with the only exception of IL-2 and IL-4, the saliva levels of cytokines in lung cancer patients insignificantly differ from the control group. However, the recognzied dynamics of the saliva cytokines level in patients with distant and regional metastasis opens the prospect of using these parameters for monitoring the treatment and controlling relapse occurrence.