An earlier study showed that plasminogen activator inhibitors (PAI) played a decisive role in the fibrinolytic level of pleural effusion, especially PAI-1, which might be related to tissue regeneration, repair and fibrosis development after pleural injury [44] .Pollack reported that UK could exert a good therapeutic effect when the formation of pleural fluid had not exceeded 6 weeks and the fibrins had not yet been widely deposited, adhered or separated [45]. Here, SERPINE1 is linked to Pleural effusion.