Amplification and specific expression of T-bet gene in nasal NK/T cell lymphoma

Abstract

To investigate the specific genetic alterations in nasal NK/T cell lymphoma (N-NK/T-L) and the significance thereof. Restriction landmark genomic scanning (RLGS) was performed on the specimen of a case of N-NK/T-L and the peripheral blood leukocytes of the same case. The RLGS image was analyzed with the Virtual genome scan (VGS) software so as to discover abnormality of T-bet gene. The discovered abnormal gene underwent cloning and preparation of probes. Southern blotting and dot blotting were performed on 3 cases of fresh N-NK/T-L tumor tissues and the genome of the case of peripheral blood lymphocytes. The expression of the T-bet (T-box expressed in T cell) gene in the tissue sections of 20 cases of N-NK/T-L, 17 cases of B cell lymphoma (BCL), 3 cases of normal spleen, and 5 cases of chronic nasopharyngitis was detected by in situ hybridization. RLGS combined with VGS revealed a genomic alteration in the T-bet gene and consequent Southern and dot blotting confirmed this genomic alteration in the N-NK/T-L cells. In situ hybridization showed that the T-bet mRNA expression rate of the N-NK/T-L cells was 90.0% (18/20), significantly higher than that of the BCL (11.8%, 2/17, P < 0.01). T-bet mRNA expression was not detected in the normal spleen and chronic nasopharyngitis tissues. The amplification and over-expression of the T-bet gene may play a role in the development of N-NK/T-L. The potential value of over-expression of T-bet gene in diagnosis of N-NK/T-L is worth further investigating.