Prevalence and relevance of EBV latency in nasopharyngeal carcinoma in Israel

Nasopharyngeal Carcinoma in Children, Current Treatment Approach

Nasopharyngeal carcinoma (NPC) is a rare and locally aggressive form of childhood cancer. Treatment of pediatric NPC includes chemotherapy and radiotherapy. Most studies on the treatment of pediatric NPC are single-arm studies. With current treatment protocols survival rates for patients with nonmetastatic disease exceed 80%, although most children will have long-term treatment-related late effects. Efforts to reduce early and late toxicities include reduced radiotherapy doses in children with good responses to induction chemotherapy. Further studies are needed to evaluate the role of immunotherapy in both the primary setting and in children with progressive or relapsed disease. This review summarizes current clinical approaches to the treatment of pediatric NPC.

Precision medicine in nasopharyngeal carcinoma: comprehensive review of past, present, and future prospect

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy with high propensity for lymphatic spread and distant metastasis. It is prominent as an endemic malignancy in Southern China and Southeast Asia regions. Studies on NPC pathogenesis mechanism in the past decades such as through Epstein Barr Virus (EBV) infection and oncogenic molecular aberrations have explored several potential targets for therapy and diagnosis. The EBV infection introduces oncoviral proteins that consequently hyperactivate many promitotic pathways and block cell-death inducers. EBV infection is so prevalent in NPC patients such that EBV serological tests were used to diagnose and screen NPC patients. On the other hand, as the downstream effectors of oncogenic mechanisms, the promitotic pathways can potentially be exploited therapeutically. With the apparent heterogeneity and distinct molecular aberrations of NPC tumor, the focus has turned into a more personalized treatment in NPC. Herein in this comprehensive review, we depict the current status of screening, diagnosis, treatment, and prevention in NPC. Subsequently, based on the limitations on those aspects, we look at their potential improvements in moving towards the path of precision medicine. The importance of recent advances on the key molecular aberration involved in pathogenesis of NPC for precision medicine progression has also been reported in the present review. Besides, the challenge and future outlook of NPC management will also be highlighted.

The Correlation between Risk Factors and Epstein-Barr Virus Serum Antibody with Histopathological Typing of Nasopharyngeal Carcinoma

BACKGROUND: The risk-combination of genetic or familial history, environmental risk factors, and EBV infection might cause nasopharyngeal carcinogenesis. The serum antibody for EBV IgA, namely, EBNA1+VCA-p18 has a good sensitivity as an early diagnostic test for nasopharyngeal carcinoma (NPC). AIM: This study aims to determine the correlation between risk factors and histopathological typing of NPC and also the correlation between the IgA [EBNA-1 + VCA p-18] ELISA and histologic type. METHODS: A cross-sectional method was used on 108 NPC patients which filled a questionnaire through an in-depth interview on the family condition to cancer, habit/lifestyle, and environmental risks. A total of 47 subjects were willing to donate blood samples for IgA [EBNA1 + VCA p-18] ELISA. Furthermore, Kendall’s tau-b (τ) correlation test was performed on NPC keratin type (WHO-1) and non-keratin (WHO-2 and 3). RESULTS: The results showed that the family history of non-keratinized NPC was associated with NPC WHO-3 as demonstrated by τ = 0.473, as well as salt-eating with τ = 0.334, smoked/grilled fish/meat eating τ = 0.205, instant noodle-eating τ = 0.356, consuming canned/packaged canned foods τ = 0.240, and flavored food eating habits τ = 0.364, along with passive smoking τ = 0.377, and chronic nasopharyngeal infection τ = 0.530. The IgA titers, namely, [EBNA1 + VCA p-18] ELISA for non-keratin type NPC was greater than the keratin type; however, it was not related to WHO-3 NPC as indicated by τ = 0.376, and p = 0.011 put this underlying before however. CONCLUSIONS: The positivity of IgA [EBNA-1 + VCA p-18] ELISA does not correlate with the non-keratin type histologic NPC, family history, as well as salt-eating, instant noodle, and flavored food eating habits, along with passive smoking and nasopharyngeal infection.

Nasopharyngeal carcinoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations

Nasopharyngeal carcinoma (NPC) is a rare pediatric tumor. Collaborative studies performed over the last decades showed improved results compared to historical data, but standardized guidelines for diagnosis and management of pediatric NPC are still unavailable. This study presents a European consensus guideline for the diagnosis and treatment of pediatric NPC developed by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT). Main recommendations include induction chemotherapy with cisplatin and 5-flurouracil, concomitant chemoradiotherapy in advanced disease, and to consider maintenance treatment with interferon beta (IFN-β) for selected high-risk patients. Dose adjustments of radiotherapy based on response to induction chemotherapy may decrease the rates of long-term treatment-related complications that affect most of the survivors.

CpG methylation in cell-free Epstein-Barr virus DNA in patients with EBV-Hodgkin lymphoma

Epstein-Barr virus (EBV) is associated with a variety of tumors and nonmalignant conditions. Latent EBV genomes in cells, including tumor cells, are often CpG methylated, whereas virion DNA is not CpG methylated. We demonstrate that methyl CpG binding magnetic beads can be used to fractionate among sources of EBV DNA (DNA extracted from laboratory-purified virions vs DNA extracted from latently infected cell lines). We then applied the technique to plasma specimens and showed that this technique can distinguish EBV DNA from patients with EBV-associated tumors (nasopharyngeal carcinoma, Hodgkin lymphoma) and viral DNA from patients without EBV-associated tumors, including immunocompromised patients and patients with EBV(-) Hodgkin lymphoma.

Negative plasma Epstein-Barr virus DNA nasopharyngeal carcinoma in an endemic region and its influence on liquid biopsy screening programmes

BACKGROUND

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) in endemic regions may have undetectable plasma EBV DNA.

METHODS

We prospectively recruited 518 patients with non-metastatic NPC and measured their pre-treatment plasma EBV DNA. The stage distribution and prognosis between pre-treatment plasma EBV DNA-negative (0-20 copies/ml) and EBV DNA-positive (>20 copies/ml) patients following radical treatment were compared.

RESULTS

Seventy-eight patients (15.1%) were plasma EBV DNA-negative, and 62 in this subset (12.0%) had 0 copy/ml. Only 23/78 (29.5%) plasma EBV DNA-negative patients with advanced NPC (stage III-IVA) had strong EBV encoded RNA (EBER) positivity (score 3) in their tumours compared to 342/440 (77.7%) EBV DNA-positive patients of the same stages (p < 0.001). Though EBV DNA-negative patients had more early-stage disease (p < 0.001) and smaller volumes of the primary tumour and the positive neck nodes (p < 0.001), they had similar 5-year overall survival and cancer-specific survival to those EBV DNA-positive counterparts by stage. Similar results were also seen when plasma EBV DNA cut-off was set at 0 copy/ml.

CONCLUSIONS

Patients with low-volume NPC may not be identified by plasma/serum tumour markers and caution should be taken in its utility as a screening tool for NPC even in endemic regions.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT02476669.

Update in pediatric nasopharyngeal undifferentiated carcinoma

Many of the principles established in adults with undifferentiated nasopharyngeal carcinoma (NPC) apply to children, adolescents and young adults. However, NPC in young patients should be distinguished from the adult form by several points. This review focuses mainly on differences between adult and pediatric NPC. The role of biology and genetics in pediatric NPC is discussed. Systemic treatment modalities including type of chemotherapy induction, timing of treatment, role of immunotherapy as adjuvant treatment, or in relapsing/ metastatic diseases are reported. Radiation modalities (doses, techniques…) in children are also reviewed. Long-term effects including secondary cancers are finally be discussed in this young NPC population.

KISS1 gene suppresses metastasis of nasopharyngeal cancer via activation of the ERK1/2 pathway

We first describe the metastasis suppression function and mechanism of KISS1 and its receptor gene in nasopharyngeal cancer.

Retrospective analysis of oncogenic human papilloma virus and Epstein-Barr virus prevalence in Turkish nasopharyngeal cancer patients

Nasopharyngeal carcinoma (NPC) is associated with the Epstein-Barr virus (EBV). Human papilloma virus (HPV) has also been detected in NPC cases. In this retrospective study, we analyze the frequency of EBV and HPV infection in 82 Turkish patients with NPC. A total of 82 were evaluated for EBV and HPV. In situ hybridization (ISH) was performed for EBV. HPV-ISH and P16 immunohistochemistry used to determine the HPV status. Seventy-two of the 82 (87%) NPC patients were EBV-positive. The highest rate of EBV-positivity was found in undifferentiated NPC patients, which accounted for 65 of 68 (95.6%) undifferentiated cases. One of the 82 NPC patients whose tumor was non-keratinizing differentiated, contained HPV. Our data shows that EBV is closely associated with NPC in Turkey. We found lower rates of HPV-positivity in NPC patients than in North American populations. In addition, both EBV and HPV-negativity were more associated with decreased survival than EBV-positive cases.

Molecular screening for Epstein Barr virus (EBV) among Sudanese patients with nasopharyngeal carcinoma (NPC)

Objective

The aim of this study was to screen for the presence of Epstein Barr Virus (EBV) among Sudanese patients with Nasopharyngeal Carcinoma (NPC).

Methods

In this study, 150 tissue samples that were previously diagnosed as having NPC were screened for the presence of EBV using Polymerase Chain Reaction (PCR). PCR was performed to amplify two viral genes; EBV nuclear antigen-4 (EBNA-4) and latent membrane protein-1 (LMP1).

Results

EBV genes were detected in 92/150 (61.3%) tissue samples. Of the 92 infected samples, 58/92 (63%) were found among males and 34/92 (37%) were among females.

Conclusion

EBV is prevalent in the Sudan and responsible of the vast majority of cases of NPC.

The Epstein-Barr virus-encoded microRNA MiR-BART9 promotes tumor metastasis by targeting E-cadherin in nasopharyngeal carcinoma

MicroRNAs (miRNAs) are a family of small RNA molecules that negatively regulate the expression of protein-coding genes and play critical roles in orchestrating diverse cellular processes. This regulatory mechanism is also exploited by viruses to direct their life cycle and evade the host immune system. Epstein-Barr virus (EBV) is an oncogenic virus that is closely associated with multiple human diseases, including nasopharyngeal carcinoma (NPC), which is a highly metastatic type of tumor and is frequently reported in South Asia. Several viral proteins have been found to promote the migration and invasiveness of NPC cells. However, not all tumor tissues express these viral oncoproteins, suggesting that other mechanisms may contribute to the aggressive behavior of NPC tumor cells. A previous sequencing study by our group revealed that the EBV miRNA miR-BART9 was expressed at high levels in all EBV-positive NPC tissues. In the present study, we used gain- and loss-of-function approaches to investigate the effect of miR-BART9 in EBV-negative and EBV-positive NPC cells. We discovered that miR-BART9 promotes the migration and invasiveness of cultured NPC cells. The promigratory activity observed in vitro was manifested as an enhanced metastatic ability in vivo. Computational analysis revealed that miR-BART9 may target E-cadherin, a membrane protein that is pivotal in preserving cell-cell junctions and the epithelial phenotype. Through biochemical assays and functional rescue analysis, we confirmed that miR-BART9 specifically inhibits E-cadherin to induce a mesenchymal-like phenotype and promote the migration of NPC cells. These results indicated that miR-BART9 is a prometastatic viral miRNA and suggested that high levels of miR-BART9 in EBV-positive NPC cells may contribute to the aggressiveness of tumor cells.

MicroRNAs (miRNAs) are a family of small RNA molecules that negatively regulate the expression of protein-coding genes and orchestrate diverse cellular processes. This regulatory mechanism is also exploited by viruses to manage their life cycle and to evade the host immune system. Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma (NPC), which is a highly metastatic type of tumor. A previous by our group study discovered that the EBV miRNA miR-BART9 is expressed at high levels in all EBV-positive NPC tissues. In the present study, we used gain- and loss-of-function approaches to investigate the function of miR-BART9 in EBV-negative and EBV-positive NPC cells. We showed that miR-BART9 promotes the migration and invasiveness of cultured NPC cells and enhances the metastatic ability of NPC tumors in vivo. Through computational analysis, we discovered that E-cadherin, a membrane protein that is critical for maintaining cell-cell contact and suppressing tumor metastasis, is a potential target for miR-BART9. Through biochemical assays and a functional rescue analysis, we confirmed that miR-BART9 specifically inhibits E-cadherin to enhance the motility of NPC cells. Our results show that miR-BART9 is a prometastatic viral miRNA and suggest that miR-BART9 may contribute to the aggressiveness of EBV-positive NPC tumors.

Downregulation of expression of transporters associated with antigen processing 1 and 2 and human leukocyte antigen I and its effect on immunity in nasopharyngeal carcinoma patients

The human leukocyte antigen (HLA)-I and antigen-processing machinery (APM) are crucial in the anti-cancer immune response. The aim of this study was to assess the clinical significance of the APM components [transporters associated with antigen processing (TAP)-1 and -2 and HLA-I] in nasopharyngeal carcinoma (NPC). A total of 58 NPC specimens and 20 healthy specimens used as control were evaluated by semiquantitative immunohistochemistry for three APM components (TAP-1, TAP-2 and HLA-I). The expression of the APM components in NPC was downregulated. CD4⁺ and CD8⁺ T cells were measured by flow cytometry and IL-10 was measured by ELISA. The number of CD8⁺ T cells and the expression of IL-10 were higher and the number of CD4⁺ T cells was lower in NPC, compared to the controls. The number of CD8⁺ T cells and the expression of IL-10 were negatively correlated with TAP-1, TAP-2 and HLA-I expression. The clinical phase, lymph node metastasis, distant metastasis, pathological type, TAP-1 expression, TAP-2 expression and HLA-I expression were identified as prognostic factors by the Kaplan-Meier analysis. A multivariate analysis using a Cox regression model indicated that distant metastasis and the downregulation of HLA-I expression were independent unfavorable prognostic factors. In conclusion, the lower expression of HLA-I induced immunosuppression in NPC patients and was associated with a poor prognosis.

Brain metastasis of nasopharyngeal carcinoma: a case report and literature review

Central nervous system metastases from nasopharyngeal carcinoma (NPC) are uncommon. The patient presented was diagnosed with aggressive advanced NPC resistant to treatment and complicated by a solitary brain metastasis. A PubMed database search was conducted to review the existing literature regarding brain metastases of NPC, using the search terms “nasopharyngeal neoplasia,” “nasopharyngeal carcinoma,” “nasopharynx,” “radiotherapy,” “central nervous system,” and “brain” in section of “Title/Abstract.” The articles were first evaluated by title and then by abstract, and thereafter appropriate manuscripts were evaluated by full text. References of the published papers were also reviewed.

Immunoassay for LMP1 in nasopharyngeal tissue based on surface-enhanced Raman scattering

BACKGROUND

Previous studies have shown that Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is closely associated with the occurrence and development of nasopharyngeal carcinoma, and can be used as a tumor marker in screening for the disease. Here we report a new methodology based on highly specific and sensitive surface-enhanced Raman scattering (SERS) technology to detect LMP1 in nasopharyngeal tissue sections directly with no need of tedious procedures as with conventional immunohistochemistry methods.

METHODS

LMP1-functionalized 4-mercaptobenzoic acid (4-MBA)-labeled Au/Ag core-shell bimetallic nanoparticles were prepared first and then applied for analyzing LMP1 in formalin-fixed paraffin-embedded nasopharyngeal tissue sections obtained from 34 cancer patients and 20 healthy controls. SERS spectra were acquired from a 25 × 25 spot square area on each tissue section and used to generate SERS images.

RESULTS

Data from SERS spectra and images show that this new SERS-based immunoassay detected LMP1 in formalin-fixed paraffin-embedded nasopharyngeal tissue sections with high sensitivity and specificity. The results from the new LMP1-SERS probe method are superior to those of conventional immunohistochemistry staining for LMP1, and in excellent agreement with those of in situ hybridization for EBV-encoded small RNA (EBER).

CONCLUSION

This new SERS technique has the potential to be developed into a new clinical tool for detection and differential diagnosis of nasopharyngeal carcinoma as well as for predicting metastasis and immune-targeted treatment of nasopharyngeal carcinoma.

The incidence of Epstein-Barr virus in nasopharyngeal carcinoma of Jordanian patients

Aim of this study was to investigate the incidence of Epstein-Barr virus (EBV) in patients diagnosed with undifferentiated nasopharyngeal carcinoma (UNPC) from the Northern Province of Jordan. All cases diagnosed with UNPC at King Abdullah University Hospital, Irbid, Jordan, between the years 1991 and 2009 inclusive were examined. Clinical data including age, gender, mode of presentation, site of biopsy were retrieved from pathology reports. In situ hybridization for (EBV)--EBERs was performed on cases with available paraffin blocks. Correlation between the different clinical variables and results of in situ hybridization was performed. There were 49 cases diagnosed with UNPC, only 39 specimens were available and studied. The median age of presentation was 41 years (range 9-70 years). Bimodal age distribution was noted, the first peak between 15 and 19 years of age and second between 60 and 64 years of age. Males were slightly more commonly affected than females. Cervical lymph node enlargement was the most common mode of presentation, followed by nasal obstruction. Biopsies were obtained primarily from the posterior nasal space, followed by cervical lymph node. Positive staining for EBERs by in situ hybridization was seen in 92.3% of the cases examined. There was no difference in detection rate between males and females or adults and pediatrics. All cases obtained from posterior nasal space were positive. The three negative cases were from biopsies obtained from cervical lymph nodes, which was statistically significant (P value <0.05). Nasopharyngeal carcinoma in Jordan is seen in both children and adults. It is associated with EBV infection in most, but not all cases. Posterior nasal space shows a more consistent staining for EBERs than cervical lymph nodes. The presence of other association with UNPC including cigarette smoking could possibly explain the cases with negative association.

Nasopharyngeal carcinoma in a south European population: epidemiological data and clinical aspects in Portugal

The incidence of nasopharyngeal carcinoma (NPC) varies worldwide, with higher rates in southern Asia, intermediate rates in Mediterranean basin countries as well as in Greenland and Alaska populations, and low rates in most of the western countries. The percentage of NPC types seems to vary according to the WHO classification. Portugal is also a Mediterranean basin country. The NPC patterns in Portuguese population is comparatively analyzed with a review of the related literature, concerning the overall incidence, male/female ratio, age of incidence, WHO type frequency, Epstein-Barr virus relationship and genetic susceptibility. The particular findings in the Portuguese population can be discussed in the light of genetic background and close relationships with potential exogenous oncogenic factors.

Heparanase expression in nasopharyngeal carcinoma inversely correlates with patient survival

AIMS

To determine the expression and prognostic significance of heparanase in nasopharyngeal carcinoma (NPC).

METHODS

Immunohistochemistry was performed on formalin-fixed paraffin-embedded sections of 46 patients with NPC. Clinical and immunohistochemical data were correlated with gender, age, histological type, Epstein-Barr virus (EBV) status, stage and survival.

RESULTS

Heparanase immunoreactivity was found in 35% (16/46) of specimens. The cumulative survival of patients diagnosed as heparanase negative (n = 30) at 10 years was 70%. In contrast, the cumulative survival of patients diagnosed as heparanase positive (n = 16) at 10 years was 25%, differences that are highly statistically significant (P = 0.03). No significant correlations were found between heparanase immunoreactivity and gender, age, EBV status, tumour histology or tumour stage.

CONCLUSION

Heparanase expression is inversely correlated with survival of NPC patients, clearly indicating that heparanase is a reliable prognostic factor for this malignancy, and further supports the notion that heparanase is a valid target for the development of anti-cancer drugs.

Detection of EBV and HPV in nasopharyngeal carcinoma by in situ hybridization

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a common cancer in Southeast Asia and is frequently associated with Epstein-Barr virus (EBV). Human papilloma virus (HPV) is an epitheliotrophic oncogenic virus that has been detected in a variety of head and neck tumors including NPC. This retrospective study was undertaken to investigate the prevalence of EBV and HPV infection subtypes 6/11 and 16/18 in 20 patients with NPC.

METHODS

In situ hybridization for EBV-encoded RNA (EBER) and tyramid signal amplification of ISH for HPV DNA subtypes 6/11 and 16/18 was performed to evaluate the prevalence of EBV and HPV latency infection among Iranian Patients with NPC.

RESULTS

16 cases were classified as WHO type III (undifferentiated carcinoma) and 4 as WHO type II (non-keratinizing SCC). EBER-ISH was positive in 19 (95%) of NPCs evaluated and in one metastases from cervical primary, included in this series. Two of 20 NPC (10%) contained HPV 6/11 sequences and two of 20 NPC (10%) contained HPV 16/18 sequences, and combined EBV and HPV infection was detected in 3 of the 20 (15%) patients.

CONCLUSION

Our data indicated that EBV is closely associated with NPC in Iran. In addition, a low percentage of EBV positive NPC contained HPV sequences. The significance of coexistence of EBV and HPV in NPC requires further study.

Role of Epstein-Barr virus DNA measurement in plasma in the clinical management of nasopharyngeal carcinoma in a low risk area

OBJECTIVE

To evaluate the role of quantitative measurement of Epstein-Barr virus (EBV) DNA in the clinical management of nasopharyngeal carcinoma (NPC) in a low tumour risk area (western Europe).

METHODS

22 consecutive Dutch NPC patients (11 europid) were studied. EBV DNA load in pretreatment and post-treatment plasma samples was determined. Three patients were also sampled at frequent intervals during treatment. RNA in situ hybridisation for the detection of EBV encoded RNAs (EBERs) was carried out on tumour biopsies of all cases.

RESULTS

All patients with EBER positive NPC (20/22) showed a positive EBV DNA load in plasma at the time of diagnosis (median EBV DNA level, 4.1 log(10) copies/ml). Patients with EBER negative NPC had no detectable EBV DNA in plasma. After treatment, complete remission was achieved in all cases and concurrently EBV DNA in plasma became undetectable in all patients. In the three longitudinally evaluated cases, EBV DNA load gradually declined towards undetectable levels within three weeks after start of treatment. Two patients developed a distant metastasis with concomitant increases in EBV viral load. In addition, one EBER positive patient developed an EBER negative metastasis in the neck during follow up and in this case EBV DNA load remained undetectable at the time of recurrence.

CONCLUSIONS

Plasma EBV DNA load measurement appears to be useful in a low tumour risk area. However, development of local recurrences may not always coincide with raised levels of EBV DNA.

Nasopharyngeal carcinoma in the pediatric age group: the northern Israel (Rambam) medical center experience, 1989-2004

Nasopharyngeal carcinoma (NPC) is rare in children, accounting for less than 1% of all malignancies. Radiation therapy has been the mainstay of treatment of many years, but to improve survival, the use of chemotherapy has been advocated. This is a retrospective analysis of 13 patients less than 20 years of age treated for NPC the Rambam Medical Center during 1989 to 2004. Eight boys and five girls with a median age of 14.5 years (range 10-19) were included. Median follow up (including patients who died) was 6.15 years (range 1-15 years). Duration of symptoms was 1 to 24 months (median 5 months). Of the 13 patients, one patient had stage I, 6 had stage III, 5 had stage IV-A, and 1 had stage IV-B disease. Ten patients (77%) had undifferentiated carcinoma (WHO type III) and three patients (23%) had nonkeratinizing carcinoma (WHO type II). Most of the children received two or three courses of neoadjuvant multiagent chemotherapy consisting of cisplatin and 5-FU, followed by radiotherapy with doses in excess of 60 Gy. One child received concomitant chemoradiation. Ten of the 13 patients (77%) are alive without disease 6 years after diagnosis (range 1-15 years). One patient developed local and distant metastases 1 year after diagnosis and is currently receiving combined radiochemotherapy. Two patients died. Overall survival was 84%; event-free survival was 77%. Nine patients (69%) developed moderate to severe long-term complications. Pediatric NPC is curable by combined radiation and chemotherapy, with doses of radiation in excess of 60 Gy. Long-term follow-up is important for early detection of second malignancies as well as for radiation-induced endocrinologic deficiencies and other normal tissue complications.

Cyclooxygenase 2 expression in nasopharyngeal carcinoma: immunohistochemical findings and potential implications

BACKGROUND

Cyclooxygenase 2 (COX-2), an inducible prostaglandin synthase, participates in inflammatory and neoplastic processes. It is expressed by various tumours and contributes to carcinogenesis. Notably, COX-2 inhibitors appear to have tumour suppressor effects and are being evaluated in clinical trials.

AIMS

To investigate COX-2 expression in nasopharyngeal carcinoma (NPC), a common tumour in parts of Asia, and to discuss potential implications.

METHODS

Eighty five cases of NPC were reviewed. COX-2 immunohistochemistry and semiquantitative assessment of expression in nasopharyngeal biopsies were performed. Because COX-2 is proangiogenic, tumour microvessel density was also assessed with the use of CD31 immunohistochemistry.

RESULTS

Histologically, 78 NPCs were undifferentiated, six were non-keratinising, and one was keratinising. Thirty nine NPCs had adjacent dysplastic epithelium. COX-2 expression was noted in 60 NPCs, 14 of 39 samples of dysplastic epithelium, and only one of 25 samples of normal epithelium (p < 0.01). Microvessel density was not significantly different between COX-2 positive and COX-2 negative tumours (p = 0.774). Tumour COX-2 positivity was not associated with higher tumour stage (p = 0.423).

CONCLUSION

COX-2 expression is more frequently seen as nasopharyngeal epithelium progresses from normal to dysplastic to carcinoma. This suggests that COX-2 contributes to the multistep process of NPC carcinogenesis. COX-2 represents a therapeutic target for COX-2 inhibitors, and there is thus a basis for the further investigation of this adjuvant treatment modality for NPC. COX-2 inhibitors are known to potentiate the antitumour effects of radiotherapy, which is the primary treatment for NPC.