Cell-free miR-10b and miR-21 as diagnostic biomarkers for malignant effusions

Abstract

11035 Background: Numerous studies have proved the roles of tissue microRNAs (miRNAs) as biomarkers in cancer diagnosis. Cell-free miRNAs from plasma or serum have been shown to be good biomarkers in the diagnosis of cancers. Here we tried to explore the potential application of cell-free miRNAs as diagnostic biomarkers to discriminate malignant effusions from benign. Methods: To obtain a molecular signature for malignant effusions, a stem-loop real-time PCR was adopted to measure the expression of 23 tumor-related miRNAs. After a pre-screening for discarding low amount miRNAs in 10 samples (5 benign/5 malignant) and a proper internal control was identified, the expression levels of 7 miRNAs were further compared among 74 malignant effusion samples (35 gastric cancer-related ascites and 39 lung cancer-related plural effusions) and 30 benign effusions. miRNAs specifically associated with malignant effusions were derived from a training group (20 malignant/10 benign) and tested in a validation group (54 malignant/20 benign). All samples were confirmed by both pathological and clinical diagnosis. Results: miR-215 was employed as the reference RNA for its abundance and consistence. The expression of miR-10b was significantly different between benign and malignant effusions (P< 0.001). Furthermore, it was showed that miR-10b can distinguish malignant plural effusions with high accuracy (areas under the curve (AUC) of receiver operating characteristic (ROC) curve 0.98, 95% CI, 0.90 to 1.0, P< 0.001), and miR-21 can be used to discriminate malignant ascites (AUC of ROC curve 0.71, 95% CI, 0.56 to 0.83, P= 0.018). Conclusions: In the present study, we demonstrated that cell-free miRNA can serve as a novel diagnostic biomarker in distinguishing malignant from benign effusions. No significant financial relationships to disclose.