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An international collaboration to harmonize the quantitative plasma Epstein-Barr virus DNA assay for future biomarker-guided trials in nasopharyngeal carcinoma.

ABSTRACT: PURPOSE:Persistently elevated posttreatment plasma EBV DNA is a robust predictor of relapse in nasopharyngeal carcinoma (NPC). However, assay standardization is necessary for use in biomarker-driven trials. We conducted a study to harmonize the method between four centers with expertise in EBV DNA quantitation. EXPERIMENTAL DESIGN:Plasma samples of 40 patients with NPC were distributed to four centers. DNA was extracted and EBV DNA copy number was determined by real-time quantitative PCR (BamHI-W primer/probe). Centers used the same protocol but generated their own calibrators. A harmonization study was then conducted using the same calibrators and PCR master mix and validated with ten pooled samples. RESULTS:The initial intraclass correlations (ICC) for the first 40 samples between each center and the index center were 0.62 [95% confidence interval (CI): 0.39-0.78], 0.70 (0.50-0.83), and 0.59 (0.35-0.76). The largest variability was the use of different PCR master mixes and calibrators. Standardization improved ICC to 0.83 (0.5-0.95), 0.95 (0.83-0.99) and 0.96 (0.86-0.99), respectively, for ten archival frozen samples. For fresh plasma with spiked-in EBV DNA, correlations were more than 0.99 between the centers. At 5 EBV DNA copies per reaction or above, the coefficient of variance (CV) was less than 10% for the cycle threshold (Ct) among all centers, suggesting this concentration can be reliably used as a cutoff for defining the presence of detectable EBV DNA. CONCLUSIONS:Quantitative PCR assays, even when conducted in experienced clinical labs, can yield large variability in plasma EBV DNA copy numbers without harmonization. The use of common calibrators and PCR master mix can help to reduce variability.

SUBMITTER: Le QT

PROVIDER: S-EPMC3630245 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature

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An international collaboration to harmonize the quantitative plasma Epstein-Barr virus DNA assay for future biomarker-guided trials in nasopharyngeal carcinoma.

Le Quynh-Thu QT Zhang Qiang Q Cao Hongbin H Cheng Ann-Joy AJ Pinsky Benjamin A BA Hong Ruey-Long RL Chang Joseph T JT Wang Chun-Wei CW Tsao Kuo-Chien KC Lo Ym Dennis YD Lee Nancy N Ang K Kian KK Chan Anthony T C AT Chan K C Allen KC

Clinical cancer research : an official journal of the American Association for Cancer Research 20130304 8

<h4>Purpose</h4>Persistently elevated posttreatment plasma EBV DNA is a robust predictor of relapse in nasopharyngeal carcinoma (NPC). However, assay standardization is necessary for use in biomarker-driven trials. We conducted a study to harmonize the method between four centers with expertise in EBV DNA quantitation.<h4>Experimental design</h4>Plasma samples of 40 patients with NPC were distributed to four centers. DNA was extracted and EBV DNA copy number was determined by real-time quantitat ...[more]

PMID: 23459720

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Project description:Nasopharyngeal carcinoma (NPC) is consistently associated with Epstein-Barr virus (EBV) infection in regions in which it is endemic, including Southern China and Southeast Asia. The high mortality rates of NPC patients with advanced and recurrent disease highlight the urgent need for effective treatments. While recent genomic studies have revealed few druggable targets, the unique interaction between the EBV infection and host cells in NPC strongly implies that targeting EBV may be an efficient approach to cure this virus-associated cancer. Key features of EBV-associated NPC are the persistence of an episomal EBV genome and the requirement for multiple viral latent gene products to enable malignant transformation. Many translational studies have been conducted to exploit these unique features to develop pharmaceutical agents and therapeutic strategies that target EBV latent proteins and induce lytic reactivation in NPC. In particular, inhibitors of the EBV latent protein EBNA1 have been intensively explored, because of this protein's essential roles in maintaining EBV latency and viral genome replication in NPC cells. In addition, recent advances in chemical bioengineering are driving the development of therapeutic agents targeting the critical functional regions of EBNA1. Promising therapeutic effects of the resulting EBNA1-specific inhibitors have been shown in EBV-positive NPC tumors. The efficacy of multiple classes of EBV lytic inducers for NPC cytolytic therapy has also been long investigated. However, the lytic-induction efficiency of these compounds varies among different EBV-positive NPC models in a cell-context-dependent manner. In each tumor, NPC cells can evolve and acquire somatic changes to maintain EBV latency during cancer progression. Unfortunately, the poor understanding of the cellular mechanisms regulating EBV latency-to-lytic switching in NPC cells limits the clinical application of EBV cytolytic treatment. In this review, we discuss the potential approaches for improvement of the above-mentioned EBV-targeting strategies.

Dataset Information

An international collaboration to harmonize the quantitative plasma Epstein-Barr virus DNA assay for future biomarker-guided trials in nasopharyngeal carcinoma.

Publications

An international collaboration to harmonize the quantitative plasma Epstein-Barr virus DNA assay for future biomarker-guided trials in nasopharyngeal carcinoma.

Similar Datasets

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