The GAS5 (growth Arrest-specific Transcript 5) Gene Fuses to BCL6 As a Result of T(1;3)(q25;q27) in a Patient with B-cell Lymphoma

The BCL6 gene is frequently disrupted at its 5' noncoding region by 3q27 chromosomal translocations in B-cell lymphoma. As a result of translocation, BCL6 is juxtaposed to reciprocal partners, such as the immunoglobulin (Ig) gene family. Besides the Ig loci, multiple non-Ig partners of the BCL6 translocation have been reported. Here we describe the identification of the GAS5 (growth arrest-specific transcript 5) gene as a novel partner of the BCL6 in a patient with diffuse large B-cell lymphoma, harboring the t(1;3)(q25;q27). In this case, the chromosome 1 breakpoint was located within the intronic small nucleolar RNA (snoRNA) sequence of GAS5 and the chromosome 3 breakpoint at 4 kb upstream of BCL6 exon 1a. As the result of chromosomal translocation, the GAS5-BCL6 chimeric transcripts were expressed, in which the 5'-terminal oligopyrimidine (5'TOP) sequence of GAS5 was fused to the whole coding sequence of BCL6. The GAS5 gene on chromosome 1q25 is the second BCL6 partner, to the SNHG5 on 6q15, which is classified as a non-protein-coding multiple snoRNA host and 5'-TOP class gene.