Immunohistochemistry expression (Fig. 6) of PAI-1 (50 vs. 20, p < 0.05) was higher and t-PA (100 vs. 160, p < 0.05) was lower in the patients with pleural-based masses compared to the patients without pleural-based masses, which was in accordance with the cytokines change trend in the pleural effusions tested by ELISA. This evidence concerns the gene PLAT and Pleural effusion.