Epstein-Barr Virus (EBV) Epithelial Associated Malignancies: Exploring Pathologies and Current Treatments

Epstein-Barr virus (EBV) is one of eight known herpesviruses with the potential to infect humans. Globally, it is estimated that between 90-95% of the population has been infected with EBV. EBV is an oncogenic virus that has been strongly linked to various epithelial malignancies such as nasopharyngeal and gastric cancer. Recent evidence suggests a link between EBV and breast cancer. Additionally, there are other, rarer cancers with weaker evidence linking them to EBV. In this review, we discuss the currently known epithelial malignancies associated with EBV. Additionally, we discuss and establish which treatments and therapies are most recommended for each cancer associated with EBV.

Racial and Ethnic Disparities in Nasopharyngeal Cancer with an Emphasis among Asian Americans

Despite the overall decreasing incidence, nasopharyngeal cancer (NPC) continues to cause a significant health burden among Asian Americans (AAs), who are a fast-growing but understudied heterogeneous racial group in the United States. We aimed to examine the racial/ethnic disparities in NPC incidence, treatment, and mortality with a specific focus on AA subgroups. NPC patients aged ≥ 15 years were obtained from the Surveillance, Epidemiology, and End Results (SEER) 18 (1975-2018). AAs were divided into Chinese, Filipino, Vietnamese, Hawaiian, Japanese, Laotian, Korean, Cambodian, Indian/Pakistani and other Asian/Pacific Islanders (APIs). Age-adjusted incidence was calculated using the SEER*Stat software. Cox proportional and Fine-Gray sub-distribution hazard models were used to calculate overall and cause-specific mortalities after adjusting for confounders. Among the total 11,964 NPC cases, 18.4% were Chinese, 7.7% Filipino, 5.0% Vietnamese, 1.2% Hawaiian, 1.0% Japanese, 0.8% Laotian, 0.8% Korean, 0.6% Cambodian, 0.5% Indian/Pakistani and 4.4% other APIs. Laotians had the highest age-adjusted NPC incidence (9.21 per 100,000), which was 18.04 times higher than it in non-Hispanic Whites (NHWs). Chinese and Filipinos observed lower overall mortalities, however, Chinese saw increased NPC-specific mortality than NHWs. Disparities in mortality were also found across different histology subtypes. This is the first and largest study examining the NPC incidence and outcomes in AA subgroups. The significant disparities of NPC within AAs underline the importance of adequate AA-subgroup sample size in future studies to understand the prognostic role of ethnicity in NPC and advocate more ethnically and culturally tailored cancer prevention and care delivery.

Adiponectin suppresses tumor growth of nasopharyngeal carcinoma through activating AMPK signaling pathway

BACKGROUND

Adiponectin is an adipocyte-secreted cytokine that enhances insulin sensitivity and attenuates inflammation. Although circulating adiponectin level is often inversely associated with several malignancies, its role in the development of nasopharyngeal carcinoma (NPC) remains unclear. Here, we investigated the clinical association between circulating adiponectin level and NPC, and examined the impact of adiponectin, as well as the underlying mechanisms, on NPC growth both in vitro and in vivo.

METHODS

The association between circulating adiponectin level and the risk of developing NPC was assessed in two different cohorts, including a hospital-based case-control study with 152 cases and 132 controls, and a nested case-control study with 71 cases and 142 controls within a community-based NPC screening cohort. Tumor xenograft model, cell proliferation and cycle assays were applied to confirm the effects of adiponectin on NPC growth in cultured cells and in xenograft models. We also investigated the underlying signaling mechanisms with various specific pharmacological inhibitors and biochemistry analysis.

RESULTS

High adiponectin levels were associated with a monotonic decreased trend of NPC risk among males in both the hospital-based case-control study and a nested case-control study. In vitro, recombinant human full-length adiponectin significantly inhibited NPC cell growth and arrested cell cycle, which were dependent on AMPK signaling pathway. The growth of xenograft of NPC tumor was sharply accelerated in the nude mice carrying genetic adiponectin deficiency. An adiponectin receptor agonist, AdipoRon, displayed strong anti-tumor activity in human xenograft models.

CONCLUSIONS

These findings demonstrated for the first time that circulating adiponectin is not only inversely associated with NPC, but also controls the development of NPC via AMPK signaling pathway. Stimulation of adiponectin function may become a novel therapeutic modality for NPC.

Treatment and outcomes of nasopharyngeal carcinoma in a unique non-endemic population

OBJECTIVE

Nasopharyngeal carcinoma (NPC) is common in Southeast Asia. Due to the influx of immigrants from this region, the incidence in British Columbia is increasing. Current literature from non-endemic populations encompasses heterogeneous cohorts. This study examines NPC in a North American population, with a high incidence, to understand the population's characteristics, treatment outcomes and recurrence patterns.

METHODS AND MATERIALS

A retrospective analysis of patients treated for primary and recurrent NPC over 15-years. Regression analyses were used to identify predictors of disease recurrence and death. A subgroup analysis of the locoregional recurrence cohort was conducted. Five-year survival outcomes were determined.

RESULTS

601 patients were included. Asian ethnicity comprised 77% and the majority had non-keratinizing carcinoma (81%). In total, 19.3% of patients experienced recurrence: 58% local, 22% regional and 20% distant. Five-year overall survival was 70%. Smoking, advancing T-stage, poorer performance status and advanced overall stage were all associated with worse overall survival (p < 0.05). Asian ethnicity improved overall survival but not recurrence free survival. Similar features in addition to non-keratinizing histology were associated with increased locoregional recurrence (p < 0.05). Competing risk analysis indicated radiotherapy alone had a higher recurrence relative to chemoradiotherapy (HR 1.91, CI 1.17-3.09, p = 0.01).

CONCLUSIONS

We report the largest study evaluating treatment and outcomes of NPC in a non-endemic population. This unique population falls between described endemic and non-endemic populations. Non-keratinizing pathology and primary radiotherapy did not affect survival; however, both had a propensity for recurrence. Finally, patients experienced more locoregional and less distant recurrence, supporting that this cohort may be amenable to curative salvage therapy.

Does East meet West? Towards a unified vision of the management of Nasopharyngeal carcinoma

Nasopharyngeal cancer (NPC) is notable for its wide geographic variation, with incidences as high as 30 in 100,000 in endemic regions but < 1 in 100,000 worldwide. This review aims to identify areas where there could be differences in prognosis, management or outcomes among countries with high or low incidence of NPC. The incidence has generally declined both in endemic and non-endemic regions throughout the years, which may be attributed to the decrease in exposure to risk factors such as early exposure to salted fish and smoking. Ethnicity has an impact both on incidence and prognosis, with Southeast Asians having the highest incidence but also better survival. Concurrent chemoradiotherapy, with or without adjuvant and/or induction chemotherapy, is the standard of care for locoregionally advanced disease, as reflected in clinical practice guidelines. Despite improvements in management, a proportion of patients relapse. Salvage treatment is associated with significant morbidity due to the critical location of the nasopharynx and the toxicities of initial therapy. Clinical expertise is paramount, but is easier to attain in endemic regions and high volume centers where enrollment of patients in clinical trials is more feasible. Collaboration between low and high incidence countries and between low and high volume facilities is key to improving NPC prognosis worldwide.

Body mass index, body shape, and risk of nasopharyngeal carcinoma: A population-based case-control study in Southern China

Whether the association between body size or shape and nasopharyngeal carcinoma (NPC) risk exists or varies by age-specific body size indicators is unclear. In a population-based case-control study conducted in Southern China between 2010 and 2014, self-reported height, weight, and body shape at age 20 and 10 years before interview were collected from 2448 histopathologically confirmed NPC cases and 2534 population-based controls. Body mass index (BMI) was categorized according to the World Health Organization guidelines for Asian populations: underweight (<18.5 kg/m2 ), normal weight (18.5-22.9 kg/m2 ), overweight (23.0-27.4 kg/m2 ), and obese (≥27.5 kg/m2 ). Multivariate odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using logistic regression. Furthermore, restricted cubic spline analysis was employed to examine nonlinear effects of BMI and body shape as continuous covariates. Underweight vs normal weight at age 20 years was associated with a 22% decreased NPC risk (OR, 0.78; 95% CI, 0.67, 0.90), whereas obesity was not significantly associated with NPC risk. Associations with BMI 10 years before the interview were similar. Having the leanest body shape at age 20 years, compared with the mode was not significantly associated with NPC risk (OR, 0.85; 95% CI, 0.62, 1.16), but having a larger body shape was associated with an elevated risk (OR, 1.25; 95% CI, 1.03, 1.52). Increasing BMI revealed positive trends with NPC risk. Despite some indication of significant findings, evidence for a strong association between BMI or body shape and NPC risk is still limited.