Satoh and colleagues thought that the effusion levels of PAI-1 on days 2 and 3 were comparable, and concluded that repeated thoracenteses did not affect the levels of PAI-1 in malignant pleural effusions. However, this is not the case. During repeated thoracenteses, the effusion levels of PAI-1 on day 2 increased significantly and remained at high levels on day 3, compared with day 1. Similarly, the effusion levels of tumor necrosis factor (TNF)-α increased significantly on day 2 and remained at high levels on day 3, compared with day 1 (see Tables 2 and 3, and Fig 1 in the article). Furthermore, the effusion levels of PAI-1 and TNF-α seen on days 2 and 3 were significantly higher in the fibrinous group than in the nonfibrinous group (see Table 3 and Fig 1 in the article). These results indicated that repeated thoracenteses increased the effusion levels of PAI-1 in patients with malignant pleural effusions, and that the increase in effusion levels of PAI-1 during repeated thoracenteses might be due to the enhanced local release of TNF-α. By contrast, the effusion levels of tissue type plasminogen activator (tPA) and the PAI-1/tPA ratio showed no significant changes during repeated thoracenteses in patients with malignant pleural effusions, either as a whole or further divided into fibrinous and nonfibrinous groups. Based on these results, it seems that the role, if any, of tPA in fibrin formation after repeated thoracenteses was limited.