SSTR2 in Nasopharyngeal Carcinoma: Relationship with Latent EBV Infection and Potential as a Therapeutic Target.

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor, most commonly located in the pharyngeal recess and endemic to parts of Asia. It is often detected at a late stage which is associated with poor prognosis (5-year survival rate of 63%). Treatment for this malignancy relies predominantly on radiotherapy and/or systemic chemotherapy, which can be associated with significant morbidity and impaired quality of life. In endemic regions NPC is associated with infection by Epstein-Barr virus (EBV) which was shown to upregulate the somatostatin receptor 2 (SSTR2) cell surface receptor. With recent advances in molecular techniques allowing for an improved understanding of the molecular aetiology of this disease and its relation to SSTR2 expression, we provide a comprehensive and up-to-date overview of this disease and highlight the emergence of SSTR2 as a key tumor biomarker and promising target for imaging and therapy.

Prognostic role of tumour-associated macrophages and regulatory T cells in EBV-positive and EBV-negative nasopharyngeal carcinoma.

AIMS: Tumour-associated macrophages (TAMs) and regulatory T cells (Tregs) form a special niche supporting tumour progression, and both correlate with worse survival in head and neck cancers. However, the prognostic role of TAM and Tregs in nasopharyngeal carcinoma (NPC) is still unknown. Therefore, we determined differences in TAMs and Tregs in different NPC subtypes, and their prognostic significance. METHODS: Tissue of 91 NPCs was assessed for TAMs and Tregs by determination of CD68, CD163, CD206 and FOXP3 expression in the tumour microenvironment. Clinicopathological correlations were assessed using Pearson X2 test, Fisher's exact test, analysis of variance and Mann-Whitney U test. Survival was analysed using Kaplan-Meier curves and Cox regression. RESULTS: CD68 and FOXP3 counts were higher in Epstein-Barr virus (EBV)-positive NPC, while CD68-/FOXP3-, CD163+/FOXP3- and CD206+/FOXP3- infiltrates were more common in EBV-negative NPC. In the whole NPC group, CD68-/FOXP3- correlated with worse overall survival (OS), and after multivariate analysis high FOXP3 count showed better OS (HR 0.352, 95% CI 0.128 to 0.968). No difference in M2 counts existed between EBV-positive and negative NPC. CONCLUSIONS: FOXP3, a Treg marker, seems to be an independent prognostic factor for better OS in the whole NPC group. Therefore, immune-based therapies targeting Tregs should be carefully evaluated. M2 spectrum macrophages are probably more prominent in EBV-negative NPC with also functional differences compared with EBV-positive NPC.

Molecular profile of nasopharyngeal carcinoma: analysing tumour suppressor gene promoter hypermethylation by multiplex ligation-dependent probe amplification.

AIMS: To assess differences in methylation profiles, and thus pathogenesis, between Epstein-Barr virus (EBV)-positive and negative nasopharyngeal carcinomas (NPCs). Also, promoter hypermethylation is a common phenomenon in early carcinogenesis to inactivate tumour suppressor genes. Since epigenetic changes are reversible, the therapeutic application of methylation inhibitors could provide treatment options. METHODS: We evaluated promoter hypermethylation profiles of 22 common tumour suppressor genes in 108 NPCs using methylation-specific multiplex ligation-dependent probe amplification. Correlation between methylation, clinicopathological features (including EBV) and survival was examined. Cluster analysis was also performed. RESULTS: Hypermethylation of RASSF1A and ESR1 was significantly more frequent in EBV-positive NPC, while hypermethylation of DAPK1 was more frequent in EBV-negative NPC. In logistic regression, age, with EBV-positive NPC occurring at earlier age, and RASSF1, with RASSF1 hypermethylation being more frequent in EBV-positive NPC, remained significant. In EBV-positive NPC, hypermethylation of RASSF1A predicted worse overall survival (OS) (HR 3.058,95% CI 1.027 to 9.107). In EBV-negative NPC, hypermethylated adenomatous polyposis coli (APC) was a predictor of poor disease-free survival (DFS) (HR 6.868, 95% CI 2.142 to 22.022). CONCLUSION: There are important epigenetic differences between EBV-negative and EBV-positive NPCs, with EBV-negative NPC having a more similar hypermethylation profile to other head and neck squamous cell carcinomas than EBV-positive NPC. Hypermethylation of RASSF1A might contribute to worse OS in EBV-positive NPC, and may be an important event in the pathogenesis of EBV-infected NPC. Hypermethylation of APC might contribute to worse DFS in EBV-negative NPC.

The prognostic role of tumor infiltrating T-lymphocytes in squamous cell carcinoma of the head and neck: A systematic review and meta-analysis.

Background - The presence of tumor-infiltrating lymphocytes (TILs) in the tumor microenvironment is associated with an improved prognosis and a better response to therapy in different types of cancer. In this systematic review and meta-analysis, we investigated the prognostic value of T cells in head and neck squamous cell carcinoma (HNSCC). Methods - In a systematic review, Pubmed and Embase were searched for publications that investigated the prognostic value of T cells in HNSCC. A meta-analysis was performed including all studies assessing the association between CD3+, CD4+, CD8+, and FoxP3+ TILs and overall survival (OS), disease-free survival (DFS), or locoregional control (LRC). Results - A pooled analysis indicated a favorable, prognostic role for CD3+ TILs (HR 0.64 (95%CI 0.47-0.85) for OS, HR 0.63 (95%CI 0.49-0.82) for DFS) and CD8+ TILs (HR 0.67 (95%CI 0.58-0.79) for OS, HR 0.50 (95%CI 0.37-0.68) for DFS, and HR 0.82 (95%CI 0.70-0.96) for LRC) in the clinical outcome of HNSCC. FoxP3+ TILs were also associated with better OS (HR 0.80 (95%CI 0.70-0.92)). Conclusion - This systematic review and meta-analysis confirmed the favorable, prognostic role of CD3+ and CD8+ T cell infiltration in HNSCC patients and found an association between FoxP3+ TILs and improved overall survival. Future studies using homogeneous patient cohorts with regard to tumor subsite, stage and treatment are necessary to provide more insight in the predictive value of TILs in HNSCC.

Prognostic role of tumor infiltrating lymphocytes in EBV positive and EBV negative nasopharyngeal carcinoma.

OBJECTIVES: Tumor infiltrating lymphocytes (TILs) correlate with both better and worse prognosis in solid tumors. As therapeutic modalities for nasopharyngeal carcinoma (NPC) are limited, immunotherapy could be a potential alternative. Up till now there is limited prognostic data on the role of TILs in NPC, so we assessed the prognostic role of TILs in Epstein-Barr-virus (EBV) positive and negative NPC. METHODS: Tissue of 92 NPCs was assessed for CD3, CD4, CD8, PD1 and PDL1 expression in the tumor's micro-environment. Correlations between clinicopathological characteristics was assessed using the Pearson X2 test, Fisher's exact test and ANOVA. Survival was analyzed with the Kaplan-Meier method and Cox regression. Differences in CD3, CD4, CD8, PD1, PDL1 counts/(co)expression between EBV positive and negative NPCs were evaluated using the Mann-Whitney U test. Two-tailed P values below 0.05 were considered statistically significant. RESULTS: EBV positive NPC contains significantly more CD3, CD4 and CD8 TILs than EBV negative NPC. In the whole NPC group, increased CD8 count is associated with better overall survival (OS) (HR 0.219 (95%CI 0.075-0.640)), but also in cases with PDL1 co-expression (HR 0.073 (95%CI 0.010-0.556)). In EBV positive NPC co-expression of CD8 and PDL1 showed better disease free survival (HR 0.407 (95%CI 0.195-0.850)) and OS (HR 0.170 (95%CI 0.037-0.787)). CONCLUSIONS: Although TILs are significantly different between EBV positive and negative NPCs, it is especially composition of the infiltrate which determines prognosis. Effects of PD1 and CD8 need more study, because these findings show much potential in using immunotherapeutic modalities in NPC treatment.

Prognostic significance of the EGFR pathway in nasopharyngeal carcinoma: a systematic review and meta-analysis.

OBJECTIVE: To evaluate the prognostic impact of the EGF receptor (EGFR) pathway molecules and assess their clinical usefulness. METHODS: We conducted a systematic review. Pubmed and EMBASE were searched January 2014. The prognostic relevance of EGFR, JAK, PI3K, PIK3CA, STAT3, STAT5, PTEN, AKT, mTOR, GRB2, SOS, RAF, RAS, MAPK, ERK, MEK and CCND1 in nasopharyngeal carcinoma was assessed. The outcomes considered were overall survival, disease-free survival and tumor-node-metastasis stage. Twenty-two studies were included. Risk of bias was evaluated. Meta-analysis for which pooled hazard ratios and 95% CIs were calculated. CONCLUSION: EGFR overexpression predicts a worse overall survival and disease-free survival in nasopharyngeal carcinoma, but no specific causal pathway molecule could be identified.