Overexpression of Epstein-Barr Virus-encoded microRNA-BART7 in Undifferentiated Nasopharyngeal Carcinoma

To validate Epstein-Barr virus BamHI-A rightward transcript 7 microRNA (ebv-miR-BART7) expression in plasma from patients with nasopharyngeal carcinoma (NPC) and explore the oncogenic role of ebv-miR-BART7 in NPC cells. Plasma ebv-miR-BART7 levels were measured using real-time quantitative RT-PCR. Effects on cell proliferation, invasion, migration, and resistance to cisplatin were studied on NPC cells using real-time cell analyzer. The plasma ebv-miR-BART7 level was significantly higher in patients with NPC in comparison with that from healthy individuals. The ebv-miR-BART7 was detectable in all the patient plasma samples and was independent of the EBV DNA level. In vitro expression of ebv-miR-BART7 enhanced proliferation, migration, and invasion of NPC cells. Furthermore, NPC cells expressing ebv-miR-BART7 were more resistant to cisplatin. High-throughput gene expression analysis suggested that ebv-miR-BART7 affects multiple cancer-related pathways. Our results indicate that plasma ebv-miR-BART7 could be used in NPC screening, especially in cases where EBV DNA is not detectable. The association of ebv-miR-BART7 with common oncogenic pathways suggests that ebv-miR-BART7 is a potential biomarker for undifferentiated NPC.