Up-regulation of the expression of S100A8 and S100A9 in lung adenocarcinoma and its correlation with inflammation and other clinical features.

Background: S100A8 and S100A9 are two members of the S100 protein family characterized by the presence of two Ca2+-binding sites of the EF-hand type. Previous studies suggested that the whole S100 family displays significant functions in tumor growth, progression and invasion. This study aimed to determine the expression of the two indices of the family, S100A8 and S100A9, in lung cancer tissues and normal lung tissues and its correlation with clinical features.

Methods: A total of 60 cases with a variety of clinical data that were diagnosed with different histological subtypes of lung cancer were investigated. Semi-quantitative reverse transcriptase-PCR (Sq-Rt-PCR) and immunohistochemical staining of cancer, adjacent and peripheral lung tissues were executed to distinguish the expression patterns of S100A8 and S100A9 and to further clarify their correlation with clinical features.

Results: Immunohistochemical staining of both proteins showed a significant up-regulation in lung cancer tissue (S100A8, S100A9, P<0.0001), and PCR revealed that the levels of S100A8 and S100A9 expression were significantly higher in lung cancer tissues (S100A8 P=0.002/0.004; S100A9 P=0.022/0.026). The higher expression was found to be correlated with the clinical characteristics of adenocarcinoma, inflammation and stage IV lesion.

Conclusions: S100A8, S100A9 up-regulation was found in the lung adenocarcinoma and end stage lung cancer tissue, the correlation of which with their higher expression in inflammatory lung tissues may indicate the collaborative effect of inflammation on the progression of cancer.