Quantitative analysis of circulating cell-free Epstein-Barr virus (EBV) DNA levels in patients with EBV-associated lymphoid malignancies

Plasma EBV quantification is associated with the efficacy of immune checkpoint blockade and disease monitoring in patients with primary pulmonary lymphoepithelioma-like carcinoma

Objectives

Primary pulmonary lymphoepithelioma-like carcinoma (PLELC) is a subtype of lung carcinoma associated with the Epstein-Barr virus (EBV). The clinical predictive biomarkers of immune checkpoint blockade (ICB) in PLELC require further investigation.

Methods

We prospectively analysed EBV levels in the blood and immune tumor biomarkers of 31 patients with ICB-treated PLELC. Viral EBNA-1 and BamHI-W DNA fragments in the plasma were quantified in parallel using quantitative polymerase chain reaction.

Results

Progression-free survival (PFS) was significantly longer in EBNA-1 high or BamHI-W high groups. A longer PFS was also observed in patients with both high plasma EBNA-1 or BamHI-W and PD-L1 ≥ 1%. Intriguingly, the tumor mutational burden was inversely correlated with EBNA-1 and BamHI-W. Plasma EBV load was negatively associated with intratumoral CD8+ immune cell infiltration. Dynamic changes in plasma EBV DNA level were in accordance with the changes in tumor volume. An increase in EBV DNA levels during treatment indicated molecular progression that preceded the imaging progression by several months.

Conclusions

Plasma EBV DNA could be a useful and easy-to-use biomarker for predicting the clinical activity of ICB in PLELC and could serve to monitor disease progression earlier than computed tomography imaging.

How to Identify Patients at High Risk of Developing Nasal-Type, Extranodal Nature Killer/T-Cell Lymphoma-Associated Hemophagocytic Syndrome

Nasal-type, extranodal nature killer (NK)/T-cell lymphoma-associated hemophagocytic syndrome (NK/T-LAHS) is a rare and life-threatening disease, requiring investigation of risk stratification. We conducted a retrospective study and proposed nomograms to predict NK/T-LAHS. The discriminative ability and calibration of the nomograms for prediction were tested using C statistics and calibration plots. We analyzed 533 patients with extranodal NK/T-cell lymphoma (ENKTL), out of which 71 were diagnosed with hemophagocytic syndrome (HPS), with a cumulative incidence of 13.3%. Significant difference for 2-year survival was found between patients with and without HPS (14.7% vs. 77.5%). Analyses showed that Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≥2, B symptoms, and bone marrow (BM) invasion were significantly associated with NK/T-LAHS. We used these data as the basis to establish a nomogram of risk index for ENKTL (RINK). In 335 patients with available data for Epstein-Barr virus DNA (EBV-DNA), we found high viral copies (≥4,450 copies/ml) were correlated with NK/T-LAHS. When these data were added to RINK, we developed another nomogram that included EBV-DNA data (RINK-E). The nomograms displayed good accuracy in predicting NK/T-LAHS with a C-statistics of 0.919 for RINK and a C-statistics of 0.946 for RINK-E, respectively. The calibration chart also showed an excellent consistency between the predicted and observed probabilities. The proposed nomograms provided individualized risk estimate of HPS in patients with ENKTL.

Prospective observation: Clinical utility of plasma Epstein-Barr virus DNA load in EBV-associated gastric carcinoma patients

Epstein-Barr virus (EBV)-associated gastric carcinomas (EBVaGCs) may account for 8-9% of all gastric cancer (GC) patients. All previous reports on EBVaGC were retrospective. Prospective study is warranted to evaluate the exact role of EBV status in predicting the prognosis of GC. It is of special interest to figure out whether dynamic detection of plasma EBV-DNA load could be a feasible biomarker for the monitor of EBVaGC. From October 2014 to September 2017, we consecutively collected GC patients (n = 2,760) from Sun Yat-sen University Cancer Center for EBER examination. We detected EBV-DNA load in plasma and tissue samples of EBVaGC patients at baseline. Subsequently, plasma EBV-DNA load was dynamically monitored in EBVaGC patients. The overall prevalence of EBVaGC is 5.1% (140/2,760). The incidence rate of EBVaGC decreased with advanced AJCC 7th TNM stage (p < 0.001), with the corresponding percentages of 9.3, 9.9, 6.7 and 1.4% for Stage I, II, III and IV patients. EBVaGC patients were predominately young males with better histologic differentiation and earlier TNM stage than EBV-negative GC (EBVnGC) patients. EBVaGC patients were confirmed to had a favorable 3-year survival rate (EBVaGC vs. EBVnGC: 76.8% vs. 58.2%, p = 0.0001). Though only 52.1% (73/140) EBVaGC patients gained detectable EBV-DNA and 43.6% (61/140) reached a positive cutoff of 100 copies/ml, we found the plasma EBV-DNA load in EBVaGC decreased when patients got response, while it increased when disease progressed. Our results suggested that plasma EBV-DNA is a good marker in predicting recurrence and chemotherapy response for EBVaGC patients.

Plasma Epstein-Barr virus DNA as an archetypal circulating tumour DNA marker

Analysis of circulating tumour DNA (ctDNA), as one type of ‘liquid biopsy’, has recently attracted great attention. Researchers are exploring many potential applications of liquid biopsy in many different types of cancer. In particular, it is of biological interest and clinical relevance to study the molecular characteristics of ctDNA. For such purposes, plasma Epstein–Barr virus (EBV) DNA from patients with nasopharyngeal carcinoma (NPC) would provide a good model to understand the biological properties and clinical applications of ctDNA in general. The strong association between EBV and NPC in endemic regions has made plasma EBV DNA a robust biomarker for this cancer. There are many clinical utilities of plasma EBV DNA analysis in NPC diagnostics. Its role in prognostication and surveillance of recurrence is well established. Plasma EBV DNA has also been validated for screening NPC in a recent large‐scale prospective study. Indeed, plasma EBV DNA could be regarded as an archetypal ctDNA marker. In this review, we discuss the biological properties of plasma EBV DNA from NPC samples and also the clinical applications of plasma EBV DNA analysis in the management of NPC. Of note, the recently reported size analysis of plasma EBV DNA in patients with NPC has highlighted size as an important analytical parameter of ctDNA and demonstrated clinical value in improving the diagnostic performance of an EBV DNA‐based NPC screening test. Such insights into ctDNA analysis (including size profiling) may help its full potential in cancer diagnostics for other types of cancer to be realised. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

(-)-Epigallocatechin-3-gallate inhibition of Epstein-Barr virus spontaneous lytic infection involves downregulation of latent membrane protein 1

The Epstein-Barr virus (EBV) lytic cycle contributes to the development of EBV-associated diseases. EBV-encoded latent membrane protein 1 (LMP1) is key to EBV lytic replication, and our previous work indicated that epigallocatechin-3-gallate (EGCG) inhibited constitutive EBV lytic infection through the suppression of LMP1-activated phosphoinositide 3-kinase/Akt and mitogen-activated protein kinase kinase/extracellular signal-related protein kinase 1/2 signaling. The present study demonstrated that LMP1 in CNE-LMP1 constructed cells significantly induced the expression of the EBV lytic proteins BZLF1 (P<0.001) and BMRF1 (P<0.05) compared with CNE1 cells. Following treatment with a specific DNAzyme that targets LMP1, significantly reduced protein expression levels of BZLF1 and BMRF1 in EBV-associated epithelial carcinoma CNE1-LMP1 cells (P<0.001 and P<0.01, respectively) and lymphoma B95.8 cells (both P<0.01) were observed. Furthermore, EGCG significantly inhibited the mRNA and protein expression levels of LMP1 (P<0.05) in an apparent dose-dependent manner in CNE1-LMP1 and B95.8 cells. Thus, the present findings indicated that the molecular mechanism underlying EGCG inhibition of EBV lytic infection involves downregulation of LMP1.

A new diagnostic marker for secreted Epstein-Barr virus encoded LMP1 and BARF1 oncoproteins in the serum and saliva of patients with nasopharyngeal carcinoma

PURPOSE

EBV has been associated with nasopharyngeal carcinomas (NPC). In North Africa, the incidence is bimodal-the first peak occurring at approximately 20 years of age and the second peak occurring at approximately 50 years. Standard diagnostic tests based on immunofluorescence using anti-IgA EBV have shown that young North African patients have a negative serology compared with older patients. We are interested in two EBV-encoded oncoproteins, LMP1 and BARF1, which have thus far not been studied in terms of their potential as diagnostic markers for NPC. These two viral oncoproteins have been detected in cell culture media, so we tested whether they could be detected in the serum and saliva of patients with NPC.

EXPERIMENTAL DESIGN

LMP1 and BARF1 proteins were analyzed in the sera and saliva of young patients and adult patients with NPC from North Africa and China. We then examined whether the secreted proteins had biological activity by analyzing their mitogenic activity.

RESULTS

Both LMP1 and BARF1 were present in the serum and saliva from North African and Chinese patients with NPC. All young North African patients secreted both proteins, whereas 62% and 100% of adult patients secreted LMP1 and BARF1, respectively. From animal studies, the secreted LMP1 was associated with exosome-like vesicles. These secreted EBV oncoproteins showed a powerful mitogenic activity in B cells.

CONCLUSION

Both proteins will be a good diagnostic marker for NPC whereas BARF1 is a particularly promising marker for all ages of patients with NPC. Their mitogenic activity suggests their implication in the oncogenic development of NPC.

Quantitative analysis of cell-free Epstein-Barr virus DNA in plasma of patients with nonnasopharyngeal head and neck carcinomas

PURPOSE

We investigated the detectability of EBV DNA in the plasma of patients with non-nasopharyngeal head and neck carcinomas (NNHNC). Previous studies have shown that EBV is present in the tumor tissue of some NNHNC.

EXPERIMENTAL DESIGN

We recruited 101 patients with NNHNC and 48 healthy controls. Blood samples were taken from controls and patients before treatment. Tumor tissue samples were tested for the presence of EBV in the first 69 patients by in situ hybridization for small EBV-encoded RNA (EBER). Plasma EBV DNA was measured by real-time quantitative PCR in patients and controls.

RESULTS

Squamous cell carcinoma (SCC) was the commonest histology (78 patients) followed by lymphoepithelial carcinoma (8 patients). EBER was detected in tumor cells in 7 of 69 patients tested. All of the EBER-positive tumors were lymphoepithelial carcinoma. Two controls (2 of 48; 4.2%) had detectable plasma EBV DNA. Plasma EBV DNA was detected in all of the patients with EBER-positive tumors, and in 23 of 94 (24.5%) patients with tumors of EBER-negative or unknown status. The proportion of plasma EBV DNA-positive cases in either group was significantly higher than that in the control group (P < 0.0027). Plasma EBV DNA concentrations in patients with EBER-positive tumors (median, 3827 copies/ml) were significantly higher than those in the controls (median, 0 copy/ml; P = 0.0001). Of patients with SCC, 21 (26.9%) had detectable plasma EBV DNA (median concentration, 34 copies/ml). Plasma EBV DNA concentrations in the whole group of patients with SCC (median, 0 copy/ml; interquartile range, 0-4 copies/ml) were also significantly higher than those in the controls (P = 0.001).

CONCLUSIONS

Our data indicate that plasma EBV DNA reflects tumoral EBER status, and it may be of use as a tumor marker for EBER-positive NNHNC. The biological and clinical significance of low levels of circulating EBV DNA in the minority of patients with EBER-negative tumors remain to be elucidated.