Novel BLIMP1/PRDM1 gene mutations in B-cell lymphoma

B lymphocyte–induced maturation protein 1 (BLIMP1)/PR domain containing 1 with zinc finger domain (PRDM1) is a transcriptional repressor with a SET domain and Kruppel-type zinc fingers. BLIMP1/PRDM1 is expressed in a subset of germinal center B cells and in all plasma cells, and it is required for terminal B-cell differentiation. Mutations of the BLIMP1 gene have been reported in patients with diffuse large B-cell lymphoma. Here, we describe novel mutations in the BLIMP1 gene in 2 of 15 (13%) cases of B-cell lymphoma (two cases of primary effusion lymphoma and 13 cases of diffuse large B-cell lymphoma). A tandem 10–base pair duplication (5′-GCTGAGTTTG-3′) was found in exon 2 of the BLIMP1 gene in primary effusion B-cell lymphoma. We also found in diffuse large B-cell lymphoma a single base substitution in exon 6 (1747C→T) that results in a somatic nonsense mutation (Q583X). These findings indicate that mutational analysis of the BLIMP1 gene may be useful for characterizing the molecular basis of B-cell lymphoma.