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

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.

To evaluate the diagnostic value of pleural fluid MUC1 and EpCAM mRNA in differentiating benign and malignant PE.

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.

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%.

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.