Novel Genetic Variant of 30-bp Deletion: A Polymorphism of Latent Membrane Protein 1 from Vietnamese Epstein Barr Virus-Associated Nasopharyngeal Carcinoma Biopsies

Nasopharyngeal carcinoma (NPC) is the most common cancer of in the areas of head and neck cancer, which gravitates toward Asia. NPC is tightly associated with the gene expression of Epstein Barr Virus (EBV). Among them, Latent membrane protein 1 ( LMP-1 ) gene, and its 30-bp deleted variant have profound effects on many pathways of NPC pathogenesis leading to the tumorigenesis. The study of the 30-bp deleted variant was not performed in Vietnam, the high endemic NPC country. Therefore, the aim of the current study is to analyze the genetic characteristics of whether present a 30-bp deletion in NPC biopsy tumors is associated with EBV. Twenty biopsy NPC samples were collected from local patients, analyzed by PCR-sequencing and compared to the prototype B95-8 30-bp deletion variant. As the results, the 30-bp deletion polymorphism was recorded in 55.00% samples. The 30-bp deletion polymorphism yielded from nucleotide 168 285 to nucleotide 168 256, different from the prototype B95-8 and other previously reported sequences. Therefore, we termed as the new 30-bp deletion* observed in the region of CDS LMP-1 gene. Three patterns of amino acid substitution/deletion observed in 30-bp deletion/no 30-bp deletion in LMP-1 C-cytoplasmic terminus were recorded. In conclusion, the new 30-bp deletion* variant, which was different from previously reported 30-bp deletion, as well as the pattern of amino acid substitution/deletion was investigated in the Vietnamese nasopharyngeal carcinoma biopsy samples.