Association between EBNA2 and LMP1 subtypes of Epstein-Barr virus and nasopharyngeal carcinoma in Thais.

BACKGROUND

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated malignancy that is common in Thailand. The association of the EBV nuclear antigen 2 gene (EBNA2) and the latent membrane protein 1 gene (LMP1) with NPC is unclear.

OBJECTIVE

To determine the association between EBNA2 and LMP1 subtypes of EBV and NPC in Thais.

STUDY DESIGN

EBV DNA from blood samples of 75 Thai patients with NPC and 44 age-matched controls was examined by PCR for EBNA2 subtypes (EBV type 1 and type 2) and LMP1 subtypes (wild-type LMP1 (wt-LMP1) and LMP1 containing a 30-bp deletion (del-LMP1)).

RESULTS

The frequencies of EBV type 1 in cases (96.0%) and controls (97.7%) were similar. The frequency of del-LMP1 in cases (58.7%) was higher than in controls (36.4%) (p=0.023). Among NPC patients, the frequency of del-LMP1 in stages III and IV (65.6%) was higher than in stages I and II (18.2%) (p=0.006). By analyzing nucleotide sequence of the LMP1 region, a new subtype, Thai1, was identified.

CONCLUSION

LMP1 subtypes of EBV may be involved in NPC susceptibility. The del-LMP1 variant may be a useful molecular marker for early detection, diagnosis and prognosis of Thai patients with NPC.