AIM: To study the EBV   LMP-1   gene integrated in the chromosome of poorly differentiated nasopharyngeal carcinoma cell line SUNE-1.  METHODS: The   LMP-1   gene of SUNE-1 was detected with PCR;   Deletion of   LMP-1   was examined by restriction endonuclease analysis and PCR. The deletion was precisely localized by DNA sequencing. RESULTS:  The   LMP-1   gene integrated in the chromosome of SUNE-1 could be deleted or non-deleted. The two introns of   LMP-1   gene were shown being lost in SUNE-1 cell line. CONCLUSION: Deletion of intron 1 and intron 2 happen in some of the   LMP-1   gene integrated in the chromosome of SUNE-1.