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Plasma Cell‐free Epstein‐Barr Virus DNA Quantitation in Patients with Nasopharyngeal Carcinoma: Correlation with Clinical Staging

Nasopharyngeal carcinoma (NPC) is an important cancer in southern China and Southeast Asia.1 In Hong Kong, nearly all NPC cases are undifferentiated or poorly differentiated and harbor Epstein-Barr virus (EBV) in tumoral tissues.1 The recent interest in the presence of tumor-derived DNA in the plasma and serum of cancer patients has prompted our group2 and Mutirangura et al.3 to look for EBV DNA in the plasma and serum of NPC patients. Our preliminary data indicate that this approach is sensitive and specific for NPC.2 Our core technology for EBV DNA detection is real-time quantitative PCR,4 which is able to provide a quantitative measurement of the concentrations of EBV DNA in the plasma of NPC patients. In this communication, we report our latest results based on an expanded sample size, thus allowing a better understanding of the relationship between circulating EBV DNA and NPC staging.