Abstract: Objective To investigate the correlation between plasma EBV-DNA level and clinical stage of untreated nasopharyngeal carcinoma （UNPC）. Methods Clinical stage of the UNPC patients was determined by tumor node metastasis （TNM）,and the content of EBV DNA in 57 UNPC patients was detected by fluorescence quantitative PCR. Result EBV-DNA positive rate was not correlated with gender and age of patients,but plasma EBV-DNA concentration of stage Ⅲ patients was higher than stage Ⅳ patients （P<0.05）. EBV-DNA positive rate of patients was increased with the development of T stage progress. The EBV-DNA concentration of stage T₄ patients was higher than stage T₂ patients （P<0.05）. No significant difference of plasma EBV-DNA concentration between the stage M and stage N patients. Conclusion The level of plasma EBV-DNA concentration is positively correlated with clinical stages of nasopharyngeal carcinoma. Detection of plasma EBV-DNA by fluorescence quantitative PCR is a useful auxiliary method for UNPC diagnosis.

Key words: Real-time PCR, Nasopharyngeal carcinoma, Epstein-barr virus EBV