However, upon stimulation, CD4+ T cells in MPE secrete higher levels of IFN-γ, IL-6 and IL-17A and lower levels of IL-10 compared to that of non-malignant tuberculous pleural effusions (TPE) over time, suggesting that Th17s may maintain a pro-inflammatory environment in the pleural cavity of lung cancer patients [138] (Fig. 6). This evidence concerns the gene CD4 and lung cancer.