Blimp-1 is a tumor suppressor gene in lymphoid malignancies.

B lymphocyte-induced maturation protein (Blimp-1) is a transcriptional factor, which controls the terminal differentiation of mature B cells to plasma cells. Blimp-1 is also called positive regulatory domain I-binding factor-1 (PRDI-BF1) or PR (PRDI-BF1-RIZ) domain zinc finger protein 1 (PRDM1). Furthermore, Blimp-1 is located in chromosome 6q21-22.1, a region frequently deleted in several tumors including lymphoid malignancies and has been supposed to be a candidate of tumor suppressor gene. Recently, mutational inactivation of Blimp-1 has been identified in a subset of diffuse large B-cell lymphomas of the activated B-cell type. In addition, an important role for Blimp-1 in maintaining the homeostasis of effector T cells is emerging and high expression of Blimp-1beta, a splicing variant of Blimp-1, have been presumed to be associated with poor prognosis in T cell lymphoma although this aspect of the gene needs further investigation. For this reason, we focused on the tumor suppressor function of Blimp-1 on not only B but also T cell malignancies in this review.