Diagnostic value of MUC1 and EpCAM mRNA as tumor markers in differentiating benign from malignant pleural effusion.

BACKGROUND: The sensitivity of conventional cytology for the detection of tumor cells in pleural effusion (PE) is inadequate. Mucine 1 (MUC1) and epithelial cell adhesion molecule (EpCAM) are two frequently and intensely expressed tumor-associated antigens in malignancies of epithelial origin. OBJECTIVE: To evaluate the diagnostic value of pleural fluid MUC1 and EpCAM mRNA in differentiating benign and malignant PE. METHOD: Fifty-eight patients with malignant PE and 40 patients with benign PE were included in this study. Pleural fluid MUC1 and EpCAM mRNA levels were measured by quantitative real-time PCR. Carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (Cyfra21-1) were also detected simultaneously. The receiver operating characteristic (ROC) curves were constructed to assess diagnostic performance of the four tumor markers in PE. RESULTS: For the diagnosis of malignant PE, MUC1 and EpCAM mRNA had larger area under ROC curves (0.916 and 0.922) and higher sensitivity (67.2 and 70.7%) with the same specificity, when compared with CEA and Cyfra21-1 (0.821 and 0.780; 48.3 and 44.8%, respectively). By combining cytology with MUC and EpCAM, a positive result indicating the presence of malignancy was achieved in 87.9%, with a good specificity of 95%. CONCLUSIONS: Compared with CEA and Cyfra21-1, the performance of MUC1 and EpCAM mRNA in malignant PE diagnosis was better. MUC1 and EpCAM mRNA in combination with cytology is a highly sensitive and specific diagnostic tool for detecting malignancy in PE.