Prognostic Significance of the Epstein-Barr Virus, p53, Bcl-2, and Survivin in Nasopharyngeal Cancer

Abstract

Purpose: Nasopharyngeal cancer (NPC) is a malignant epithelial carcinoma which is intimately associated with EBV. The latent presence of EBV affects the function of p53, Bcl-2, and survivin. We thus investigated the relationship between EBV status, p53, Bcl-2, and survivin in biopsy specimens from patients with primary NPC. Experimental Design: Archival formalin-fixed, paraffin-embedded NPC biopsies were evaluated in 80 patients treated with curative radiation from a single institution. The presence of EBV was determined using EBER in situ hybridization, whereas p53, Bcl-2, and survivin were assessed using immunohistochemistry. Results: The majority of NPC specimens in this patient cohort were EBER-positive (64 of 78, or 82%), which in turn, was significantly associated with ethnicity (P = 0.0007), and WHO subtype 2A/2B (P = 0.04). EBER-positive tumors were also associated with p53 (P = 0.002), Bcl-2 (P = 0.04), and nuclear survivin (P = 0.03) expression. Patients with EBER-positive NPC fared better, with a 10-year overall survival of 68% versus 48% for EBER-negative patients (P = 0.03). For nuclear survivin, patients with either low or high nuclear survivin fared worse than patients with intermediate survivin expression (P = 0.05), suggesting that there is an optimal proportion of survivin-expressing cells for best function and clinical outcome. Conclusions: With an extended median follow-up time of 11.4 years, EBV status remains a strong predictor for overall survival in NPC. EBV-positive NPC has strong molecular associations with p53, Bcl-2, and survivin expression. Furthermore, we provide clinical data revealing the potentially dual nature of survivin in predicting clinical outcome.Nasopharyngeal carcinoma (NPC) is a malignant epithelial carcinoma of the head and neck site, with incidences of 20 to 30 per 100,000 people in areas such as Southeast Asia (a region of >100 million people) and the Mediterranean basin (a region of >300 million people) (1). NPC is anatomically located in close proximity to the base of the skull, rendering it a significant challenge for conventional and experimental treatments. In fact, inadequate tumor volume coverage may be partially responsible for the modest 5-year overall survival (OS) rate of f70% when patients are treated with conventional radiotherapy alone (2 -4). Although intensity-modulated radiotherapy does improve local control, the risk of distant metastases remains high at f40% (2). A predilection for developing distant metastases, a young median age of presentation (at f50 years), and the intimate association with EBV are features that render NPC a unique head and neck epithelial malignancy (5).The latent presence of EBV is unique to malignancies such as NPC, Burkitt's lymphoma, Hodgkin's lymphoma, peripheral T cell lymphomas, natural killer cell lymphomas, and gastric carcinomas (1). Approximately 75% to 81% of patients with NPC worldwide harbor the EBV genome, which is present in the type II latency. This form of latency is characterized by the expression ...

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