Identification of a 7-microRNA signature in plasma as promising biomarker for nasopharyngeal carcinoma detection

Background Circulating microRNAs (miRNAs) have become reliable sources of non-invasive biomarkers for cancer diagnosis. Identification of promising miRNA biomarkers in plasma might benefit a lot to the detection of nasopharyngeal carcinoma (NPC). Methods The Exiqon miRNA qPCR panel was used in the screening stage to identify candidate miRNAs, which were further verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) in the following three stages among plasma samples from 200 NPC patients and 189 healthy donors (as normal controls [NCs]). The identified miRNAs were further explored in tissue specimens (48 NPC vs 32 NCs) and plasma exosomes (32 NPC vs 32 NCs). Survival analyses were ultimately conducted by Cox regression models and Kaplan-Meier curves using log-rank tests. Results We identified a 7-miRNA signature including let-7b-5p, miR-140-3p, miR-144-3p, miR-17-5p, miR-20a-5p, miR-20b-5p, and miR-205-5p in plasma for NPC diagnosis after four-stage validation. The areas under the receiver operating characteristic curve (AUCs) for the signature were 0.879, 0.884, 0.921, and 0.807 for the training, testing, external validation stage, and the combined three stages, respectively. In NPC tissues, miR-144-3p, miR-17-5p, miR-20a-5p, and miR-205-5p were consistently up-regulated while let-7b-5p and miR-140-3p were significantly down-regulated compared to NCs. However, none of the seven identified miRNAs were dysregulated in plasma-derived exosomes in NPC patients. As to survival analysis, none of the seven miRNAs seemed to be associated with NPC prognosis. Conclusion We identified a 7-miRNA signature in plasma as promising non-invasive biomarkers for NPC detection.