Determination of EBV Serology and Plasma EBV DNA Load as a Combined Tool for Nasopharyngeal Carcinoma (NPC) Diagnosis

Abstract

There is limited information regarding the clinical significance of Epstein-Barr virus (EBV) markers for nasopharyngeal carcinoma NPC diagnoses and monitoring in non-endemic areas. Low NPC incidence in non-endemic countries made it difficult to form a representative group of patients for research this issue. Moreover, NPC cases are often characterized into morphologically different tumor types based upon the geographic and ethnic variability. Since viral and serological markers reflect the different biological events accompanying the development of NPC, it is important to compare their clinical value in the context of different disease manifestations. The implementation of such a study in a non-endemic region is of particular interest, allowing the investigation of the potential impact of differences in the genetic and ethnic characteristics of the population, versus those in populations from endemic regions. In present study, we analyzed clinical significance of two EBV markers (serological and molecular) in large group (96 cases) of undifferentiated non-keratinizing carcinoma of nasopharyngeal type (UNPC) Russian patients. It has been shown that IgA/VCA antibody titers elevated on patient's admission and being valuable markers for primary UNPC diagnosis do not allow to adequately assessing patients’ state after the treatment. In contrast to EBV serology, the plasma EBV DNA load was found to be valuable marker for clinical evaluation of UNPC patient’s state, such as remission and relapse. It was also shown that the concentration of viral DNA correlated with the UNPC patients' overall survival. The proposed study, conducted on UNPC patients from a non-endemic region, for the first time revealed a direct correlation between IgG /IgA antibody titers to EBV virus capsid antigen (VCA) and the levels of plasma EBV DNA load, and the absence of such correlation between plasma EBV DNA burden and serological responses to EBV. t has also been demonstrated that the combined assessment of plasma EBV DNA load and EBV-specific antibody titers provides a reliable approach to UNPC diagnosis, disease monitoring, and therapeutic response assessment.