T- and B-lymphocytes are involved in recognition of foreign antigen by the specificity of their surface T-cell receptor and immunoglobulin, generated by gene rearrangement. Each T- and B-lymphocyte carries unique rearranged TCR or immunoglobulin gene, which has been applied to detect clonal from non-clonal T- and B-cell proliferation.
Natural killer (NK)/T-cell lymphomas are frequently associated with Epstein-Barr virus (EBV), and usually lack TCR gene rearrangement. Studies from Asia have reported frequent deletion in the LMP-1 gene in EBV-associated nasopharyngeal carcinoma (NPC). The present study aims to investigate LMP-1 and TCRgamma gene status in upper aerodigestive tract lymphomas. A total of 43 cases were classified into T-, B-, and NK/T-cell tumors based on the phenotype expressions of CD3(+)/CD20(-)/CD56(-), CD3(-)/CD20(+)/CD56(-), and CD3(+)/CD20(-)/CD56(+), respectively. The presence of EBV in the tumor was confirmed by EBV early RNA-in situ hybridization. LMP-1 gene deletion and TCR gamma gene rearrangement were analyzed by polymerase chain reaction on paraffin-embedded tissues. There were 20 NK/T-, eight T-, and 15 B-cell phenotype lymphomas in the present series, and EBV was detected in 19 (95%), two (25%), and three (20%) cases in the respective groups. All EBV+ cases carried 30-bp deletion in the LMP-1 gene, and two of the NK/T-cell cases were infected by both the wild type and deleted strains. Five (25%) of the NK/T-cell phenotype lymphomas showed rearranged TCR gamma gene. The present study revealed a high frequency of EBV association, and a high frequency of 30-bp deletion in the LMP-1 gene in the virus in the present series of lymphoma. The NK/T-phenotype lymphomas are comprised of both NK-cell and cytotoxic T-lymphocyte-derived tumors.