Sequence variations of Epstein–Barr virus LMP1 gene in gastric cancer and chronic gastritis isolates from Iranian patients

AIM: The current study aimed to investigate sequence variations in the C-terminus of latent membrane protein 1 (LMP1) in Epstein-Barr virus (EBV) isolates from Iranian patients with chronic gastritis or gastric cancer (GC). BACKGROUND: LMP1, an essential viral oncoprotein, is the critical element in the immortalization of B cells. It contains a small twenty-four amino acid cytoplasmic N-terminal region, six transmembrane segments, and a two hundred amino acid cytoplasmic C-terminal domain. Most LMP1-mediated signal transduction events are moderated by some functional parts of the cytoplasmic C-terminal domain. METHODS: Thirty-two EBV-positive biopsy tissues were obtained from patients with gastric cancer and patients with chronic gastritis. The C-terminal nucleotide sequences of LMP1 were amplified using nested-PCR and analyzed by DNA sequencing. RESULTS: Four to eight copies of the 11 repeat elements (codon 254–302) were observed in the carboxyl-terminal site of patients, but no relationship was found between the number of repeat sequences and disease status. The 30-bp deletion corresponding to codon 345–354 of the B95-8 strain was observed in 34% of isolates, and the remaining samples were non-deleted. In the gastric cancer group, a higher number of 33-bp repeats (≥5 repeats) was observed in 30-bp-deletion (100%) than in non-deleted (42%) isolates, and the difference was statistically significant. Analysis revealed that a gastritis isolate may be the result of recombination between Alaskan and China1 strains. CONCLUSION: Overall, the current results showed no association between C-terminal sequence variations of LMP1 and malignant or non-malignant isolate origin.