Abstract: Objective To investigate the expression of miR-93 in plasma exosomes of patients with malignant pleural effusion and its diagnostic value for malignant pleural effusion.Methods A total of 118 patients with pleural effusion admitted to our hospital from July 2018 to August 2020 were selected as the research objects.Among them,63 patients with malignant pleural effusion were in the malignant group,and 55 patients with benign pleural effusion were in the benign group.The clinical data of all research subjects were collected,the levels of serum and pleural fluid routine indicators(pleural fluid protein,carcinoembryonic antigen,chloride ion,white blood cell count,aspartate aminotransferase,alanine aminotransferase,phosphocreatine kinase) of patients were detected;the expression level of miR-93 in plasma exosomes was detected by qRT-PCR;the correlation between miR-93 and routine indexes of patients' serum and pleural fluid was detected by Pearson method;the predictive value of plasma exosomal miR-93 level for malignant pleural effusion was evaluated by receiver operating characteristic curve(ROC).Results The level of plasma exosomes miR-93 in the malignant group was lower than that in the benign group(P＜0.05);the levels of pleural fluid protein,carcinoembryonic antigen,white blood cell count,aspartate aminotransferase,alanine aminotransferase and chloride ion in the malignant group were higher than those in the benign group(P＜0.05),and the level of phosphocreatine kinase was lower than that in the benign group(P＜0.05);miR-93 was negatively correlated with pleural fluid protein,carcinoembryonic antigen,chloride ion,white blood cell count,aspartate aminotransferase,alanine aminotransferase levels(r=-0.386、-0.363、-0.404、-0.423、-0.404、-0.453,P＜0.05),and positively correlated with phosphocreatine kinase level(r=0.462，P＜0.05);ROC results showed that the area under the curve(AUC) of plasma exosomes miR-93 predicting malignant pleural effusion was 0.972(95%CI:0.925-0.993),the corresponding sensitivity was 87.30%,and the specificity was 96.55%.Conclusion The expression level of miR-93 in plasma exosomes in patients with malignant pleural effusion is lower than that in patients with benign pleural effusion.The clinical detection of miR-93 expression has important value in the diagnosis of malignant pleural effusion.

Key words: malignant pleural effusion；exosomes；miR-93；diagnostic value