Abstract
Background Nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) infection. EBV BamHI A rightward transcripts (BART) encode microRNAs (EBV-miR-BARTs) abnormally highly expressed and play an essential role in NPC. Our previous study indicated that circulating EBV-miR-BARTs was potentially severed as a biomarker of NPC. This study aims to investigate the diagnostic and prognostic performance of miR-BART7-3p and miR-BART13-3p. Methods Plasma levels of EBV DNA, miR-BART7-3p, and miR-BART13-3p were examined by quantitative PCR in 483 treatment-naïve NPC patients and 243 controls without NPC. The prognostic performance was examined by comparing plasma levels with rates of distant metastasis during follow-up. Results Plasma EBV DNA was detected in 93.7% of NPC subjects vs. 8.6% of controls. The microRNAs BART7-3p and miR-BART13-3p were detected in 96.1% and 97.9% of NPC subjects vs. 3.39% and 3.3% of controls. The area under the receiver operating characteristic curve for diagnosing NPC was 0.926 for EBV DNA, 0.964 for miR-BART7-3p, 0.973 for miR-BART13-3p, and 0.997 for all three indices. Among 465 NPC patients without distant metastasis, the above-median miR-BART7-3p and EBV-DNA were independent risk for shorter distant metastasis-free survival (DMFS) (HR=2.94, 95%CI: 1.44-5.97, p=0.003; HR=2.27, 95%CI:1.26-4.10, p=0.006) in multivariate Cox regression. In the 245 patients who received radiotherapy, EBV DNA, miR-BART7-3p, and miR-BART13-3p were detectable immediately afterward in, respectively, 28.6%, 17.6%, and 54.7% of patients. Four-year DMFS rate was lower in patients with detectable miR-BART7-3p (73.0% vs. 89.7%, p<0.001), miR-BART13-3p (61.4% vs. 90.0%, p<0.001), and EBV-DNA (82.7% vs. 89.5%, p=0.035) after radiotherapy. In multivariate Cox regression, detectable miR-BART7-3p and EBV-DNA were independent risks for shorter DMFS (HR=4.13, 95%CI: 1.89-9.01, p<0.001; HR = 2.14, 95%CI: 1.04-4.42, p=0.039). Four-years DMFS rate was 92.0% in subjects (n=156) with neither detectable miR-BART7-3p nor EBV-DNA after radiotherapy, 80.0% in subjects (n=65) with either detectable miR-BART7-3p or EBV-DNA after radiotherapy, and 52.9% in subjects (n=24) with both detectable miR-BART7-3p and EBV-DNA after radiotherapy (p<0.001). Conclusions Circulating levels of miR-BART7-3p and miR-BART13-3p show excellent diagnostic performance for NPC. The combination of plasma levels of miR-BART7-3p and EBV DNA at diagnosis and after radiotherapy may help stratify patients by risk of poor DMFS.
Prevalence of Epstein Barr Virus in biopsy specimens of nasopharyngeal carcinoma from Serbian patients
