NFkappaB activity analysis was performed with pNFkappaB-luc reporter plasmid. Expression of NFkappaB in nuclear and expression of Igkappa in intact cells were analyzed by Western Blot to identify whether Epstein-Barr virus encoded latent membrane protein 1 (LMP1) increases the expression of immunoglobulin kappa light chain through NFkappaB signal transduction pathway in nasopharyngeal carcinoma. Results showed that LMP1 could increase NFkappaB activity and promote the accumulation of NFkappaB p65 in nucleus, and LMP1 also increased Igkappaexpression. In addition, phosphorothioate oligonucleotides to antisense NFkappaB p65 and p50 inhibited the Igkappaexpression. These imply that LMP1 can regulate Igkappa expression via NFkappaB signal transduction pathway in nasopharyngeal carcinoma.