[Significance of cell-free Epstein-Barr virus DNA in monitoring prognosis of nasopharyngeal carcinoma].
OBJECTIVE
It has been reported that cell-free Epstein-Barr virus (EBV-DNA) in plasma was useful in diagnosing and monitoring nasopharyngeal carcinoma (NPC). The current study was designed to evaluate the significance of EBV-DNA in monitoring the prognosis of nasopharyngeal carcinoma and to compare with VCA/IgA and EA/IgA.


METHODS
EBV-DNA, VCA/IgA, and EA/IgA levels in plasma were detected in different NPC patients after radiotherapy, including 30 distant metastasis patients, 22 locoregional recurrence patients, 24 remission individuals who had been followed up more than 2 years after treatment. EBV-DNA was detected using real-time quantitative PCR system;VCA/IgA and EA/IgA were tested using regular immunofluorescence. In cohort study, the indexes were tested in different radiation periods for the 20 new cases of nasopharyngeal carcinoma.


RESULTS
The median plasma EBV-DNA concentration was 135,100 copies/ml (interquartile range: 5,525-1,003,750) in metastasis group, 20,500 copies/ml (interquartile range: 0-58,500) in locoregional recurrence group and 0 copies/ml (interquartile range: 0-0) in continuous remission group (P< 0.05). The levels of VCA/IgA and EA/IgA had no significant difference in different groups. The high level of EBV-DNA concentration in metastasis group was more than that in locoregional recurrence group. At the level of 1,000,000 copies/ml, EBV DNA indicated distant metastasis of NPC with a specificity of 100% and a sensitivity of 27.3%; however, the sensitivity was 0 copies/ml in locoregional recurrence group. For the 20 new patients, EBV DNA concentration gradually decreased in the radiation period, 32,050 copies/ml (interquartile range: 3,880-317,750) before radiation, 0 copies/ml (interquartile range: 0-14,375) when 40 Gy radiation dose and 0 copies/ml (interquartile range: 0-2940) when the radiation finished (P< 0.05). However, the levels of VCA/IgA and EA/IgA had no significant difference.


CONCLUSIONS
The plasma cell-free EBV-DNA is more valuable than VCA/IgA and EA/IgA for monitoring the prognosis of NPC patients.
Cao
Su-Mei
SM
Department of Nasopharyngeal Carcinoma, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060, P.R.China. sumei_cao@21cn.com
Min
Hua-Qing
HQ
Gao
Jin-Song
JS
Hong
Ming-Huang
MH
Xiao
Xi-Bin
XB
Zhang
Chang-Qing
CQ
Liu
Xiao-Dong
XD
Zhang
Ai-Lan
AL
Guo
Xiang
X
D000956:Antigens, Viral / Q000097:blood*; D004279:DNA, Viral / Q000097:blood*; D020031:Epstein-Barr Virus Infections / Q000150:complications*; D005260:Female; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000821:virology; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011379:Prognosis
D000956:Antigens, Viral; D004279:DNA, Viral