A comparative study of cell-free Epstein-Barr virus DNA and microRNAs in nasopharyngeal carcinoma screening

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a malignant squamous cell carcinoma in the head and neck region. Epstein-Barr virus (EBV) is associated with undifferentiated NPC. Cell-free EBV DNA is routinely used as a serological marker. Circulating nucleic acids were recently suggested as non-invasive diagnosis markers. This study aims to examine the use of microRNAs (miRNAs) as a supplement to existing screening methods. METHODS: The expression levels of hsa-miR-21, hsa-miR-1301, ebv-miRBART7 and ebv-miR-BART22 were investigated in ten paired tumor-normal tissues, plasmas of sixty other NPC patients and twenty-five cohorts. Plasmas from thirteen NPC patients were evaluated for both EBV and miRNAs levels between pre-operative and post-operative (three months after radiotherapy) patients. MiRNA and EBV DNA quantitation were performed by quantitative real-time PCR and EBV quant kit, respectively. RESULTS: MiR-BART7 showed higher expression in tumor tissues (p=0.038) and in NPC plasma samples with sensitivity 71.15% and specificity 76.47%. Among patients who had already received radiotherapy, 12 of 13 patients showed elevated miR-BART7 expression whereas 4 of 13 patients showed elevated EBV DNA, 3 of 13 patients had increased and 5 of 13 undetermined. CONCLUSION: MiR-BART7 showed significantly higher expression in NPC with good sensitivity and specificity. Further studies will be undertaken on the functional role of miR-BART7.link_to_OA_fulltex