Rta-IgG as a biomarker for diagnosis and post treatment prognostic of nasopharyngeal carcinoma

Combining Epstein-Barr virus antibodies for early detection of nasopharyngeal carcinoma: A meta-analysis

OBJECTIVE

Epstein-Barr virus-related antibody seromarkers including VCA-IgA, EA-IgA, EBNA1-IgA, and Rta-IgG are used as markers for the detection of nasopharyngeal carcinoma (NPC). This meta-analysis was conducted to evaluate the diagnostic performance of their use in combined assays.

METHODS

Computerized searching of five electronic databases, supplemented by manual searching methods, was performed to identify pertinent articles. Diagnostic accuracy parameters, including sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC), were calculated with corresponding 95% confidence intervals (CIs).

RESULTS

Twenty-one studies with 4753 NPC cases and 31875 non-NPC controls were included. The pooled sensitivities for VCA-IgA+EA-IgA, VCA-IgA+EBNA1-IgA, VCA-IgA+Rta-IgG, and VCA-IgA+ EA-IgA+Rta-IgG were 0.89, 0.93, 0.94, and 0.94, respectively. Pooled specificities were 0.89, 0.88, 0.90, and 0.95, respectively. The PLRs were 8.1, 7.6, 9.4, and 17.4, respectively. Pooled NLRs were 0.12, 0.08, 0.07, and 0.07, respectively. Pooled DORs were 66, 95, 135, and 261, respectively. Pooled AUCs were 0.94, 0.96, 0.97, and 0.94, respectively.

CONCLUSION

These four combined assays based on EBV-related antibodies show diagnostic accuracy. The three-marker assay of VCA-IgA, EA IgA, and Rta-IgG has the best performance. Given the aspect of cost-benefit, VCA-IgA combined with EBNA1-IgA or Rta-IgG could become the preferred serodiagnostic strategy for NPC screening and early diagnosis.

Significance of Dynamic Changes of VCA-IgA Levels in Pre- and Post-treatment Plasma of Patients with Nasopharyngeal Carcinoma: Development of a Clinically-Oriented Model

INTRODUCTION

Nasopharyngeal carcinoma (NPC) responds well to radiotherapy but recurrence and metastasis are common. Currently, there is no widely used biomarker for accurately predicting the recurrence and metastasis of NPC. In this study, we aimed to evaluate the prognostic ability of Epstein-Barr virus (EBV) capsid antigen (VCA-IgA) kinetics by assessing the dynamic changes of VCA-IgA levels in the pre- and post-treatment plasma of patients with NPC and have proposed a prognostic model for clinical use.

METHODS

The clinical records of patients with NPC diagnosed at Sun Yat-sen University Cancer Center were retrieved and classified into a respondent (n = 83) or non-respondent (n = 25) cohort based on their response to antitumor therapy. Factors associated with the outcomes of the patients were assessed and incorporated in a nomogram. For internal validation, bootstrapping with 1000 resamples was used. The prediction accuracy and discriminative ability of the nomogram were investigated by calibration and concordance index (C-index) and plotted decision curves to assess the benefits of nomogram-assisted decisions in a clinical context.

RESULTS

Plasma VCA-IgA level of the non-respondent cohort at the 6th month after treatment was found significantly higher than the respondent cohort. Post-treatment VCA-IgA level, smoking, and distant metastases were identified as independent risk factors for disease-free survival (DFS), and were used to stratify patients with NPC into three risk groups. The median DFS of the low-, middle- and high-risk groups were 48.5, 35.0, and 15.5 months, respectively. The C-index of the nomogram was 0.848 (95% CI 0.769-0.926), demonstrating good clinical accuracy for predicting the DFS of patients with NPC. The decision curve showed that the nomogram in predicting DFS was better than VCA-IgA level, smoking, and distant metastases.

CONCLUSION

The proposed VCA-IgA-based nomogram demonstrated a promising ability to predict the DFS of patients with NPC after antitumor therapy. It could be used as a clinical guidance to improve the therapeutic/surveillance strategies of these patients.

Prognostic Value of Serum Epstein-Barr Virus Antibodies and Their Correlation with TNM Classification in Patients with Locoregionally Advanced Nasopharyngeal Carcinoma

Purpose

This study assessed the correlation between Epstein-Barr virus (EBV) biomarkers and the eighth American Joint Committee on Cancer staging system and the prognostic values of IgG antibodies against replication and transcription activator (Rta-IgG), IgA antibodies against Epstein-Barr nuclear antigen 1, and BamH1 Z transactivator (Zta-IgA) in locoregionally advanced nasopharyngeal carcinoma (NPC) patients.

Materials and Methods

Serum EBV antibody levels were measured by enzyme-linked immunosorbent assay in 435 newly diagnosed stage III-IVA NPC patients administered intensity-modulated radiation therapy±chemotherapy. The primary endpoint was progression-free survival (PFS).

Results

Rta-IgG and Zta-IgA levels were positively correlated with the N category and clinical stage. Patients with high Rta-IgG levels (> 29.07 U/mL) showed a significantly inferior prognosis as indicated by PFS (77% vs. 89.8%, p=0.004), distant metastasis–free survival (DMFS) (88.3% vs. 95.8%, p=0.021), and local recurrence-free survival (LRFS) (91.2% vs. 98.3%, p=0.009). High Rta-IgG levels were also significantly associated with inferior PFS and LRFS in multivariable analyses. In the low-level EBV DNA group (≤ 1,500 copies/mL), patients with high Rta-IgG levels had significantly inferior PFS and DMFS (both p < 0.05). However, in the high-level EBV DNA group, Rta-IgG levels were not significantly associated with PFS, DMFS, and LRFS. In the advanced T category (T3–4) subgroup, high Rta-IgG levels were also significantly associated with inferior PFS, DMFS, and LRFS (both p < 0.05).

Conclusion

Rta-IgG and Zta-IgA levels were strongly correlated with the TNM classification. Rta-IgG level was a negative prognostic factor in locoregionally advanced NPC patients, especially those with advanced T category or low EBV DNA level.

Epstein-Barr virus Rta promotes invasion of bystander tumor cells through paracrine of matrix metalloproteinase 9

Clinical studies suggest a positive association between malignant progression of nasopharyngeal carcinoma (NPC) and Rta, a transcription factor of Epstein-Barr virus (EBV). However, Rta induces cellular senescence in vitro. To provide an underlying mechanism integrating these clues, we adapted a concept of senescence-associated secretory phenotype (SASP), based on which senescent cells facilitate tumor progression through paracrine. First, Rta-expressing NPC cells themselves show reduced invasiveness but promote invasion of Rta-negative tumor cells through secreted factors. Secretion of matrix metalloproteinase 9 (MMP9), an SASP protein, is increased by Rta, which requires the C-terminus of Rta and Rta-induced activation of E2F. Furthermore, the Rta-induced, paracrine-mediated pro-invasive effect is blocked upon knockdown of MMP9 expression or treatment with an MMP9 inhibitor. This study not only indicates that Rta can contribute to NPC progression through paracrine but also supports that MMP9 is a potential therapeutic target to prevent NPC metastasis.

Epstein-Barr virus BRLF1 induces genomic instability and progressive malignancy in nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a serious health problem in China and Southeast Asia. Relapse is the major cause of mortality, but mechanisms of relapse are mysterious. Epstein-Barr virus (EBV) reactivation and host genomic instability (GI) have correlated with NPC development. Previously, we reported that lytic early genes DNase and BALF3 induce genetic alterations and progressive malignancy in NPC cells, implying lytic proteins may be required for NPC relapse. In this study, we show that immediate early gene BRLF1 induces chromosome mis-segregation and genomic instability in the NPC cells. Similar phenomenon was also demonstrated in 293 and zebrafish embryonic cells. BRLF1 nuclear localization signal (NLS) mutant still induced genomic instability and inhibitor experiments revealed that BRLF1 interferes with chromosome segregation and induces genomic instability by activating Erk signaling. Furthermore, the chromosome aberrations and tumorigenic features of NPC cells were significantly increased with the rounds of BRLF1 expression, and these cells developed into larger tumor nodules in mice. Therefore, BRLF1 may be the important factor contributing to NPC relapse and targeting BRLF1 may benefit patients.

Cyclooxygenase-2 expression is positively associated with lymph node metastasis in nasopharyngeal carcinoma

BACKGROUND

Accumulating evidence has demonstrated that cyclooxygenase-2 (COX-2) is involved in head and neck cancers, especially in nasopharyngeal carcinoma (NPC). However, the association between COX-2 expression and lymph node metastasis in NPC remains uncertain. This systematic review and meta-analysis meta-analysis investigated the relationship between COX-2 expression and lymph node metastasis and other signs of disease progression in NPC.

METHODS

Previously published studies assessing COX-2 expression and lymph node metastasis in NPC were identified in four English databases and three Chinese ones (Pubmed, Embase, Cochrane Database of Systematic Reviews, Web of Science, China National Knowledge Infrastructure, Wanfang, Vip Journal Integration Platform) up to November 2016. Quality of all eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Pooled odds ratios (OR) and their 95% confidence intervals (95%CI) were calculated with fixed-effects or random-effects model to evaluate the effects of COX-2 expression on lymph node metastasis.

RESULTS

A total of 27 studies with 1797 NPC patients met the inclusion criteria. The expression of COX-2 was significantly higher in patients with nasopharyngeal carcinoma than those without the carcinoma, with a combined OR of 21.17 (95%CI = 15.02-29.85, I2 = 35.1%, Pheterogeneity = 0.070). A statistically significant association between COX-2 expression and lymph node metastasis in NPC patients, with an OR of 4.44 (95%CI = 3.46-5.70, I2 = 38.3%, Pheterogeneity = 0.024), and with other indicators of disease progression. Subgroup analyses based on COX-2 assay and staging criteria of TNM showed no significant heterogeneity.

CONCLUSIONS

The results suggest that expression of COX-2 is associated with lymph node metastasis and disease progression in NPC, indicating a potential role in evaluation of prognosis and in treatment decisions. COX-2 inhibitors have potential in the treatment of NPC that should be further investigated.