PRDM1/BLIMP-1 expression in multiple B and T-cell lymphoma.
OBJECTIVE
The positive regulatory domain I (PRDM1) protein or BLIMP-1, belonging to the PRDM gene family of transcriptional repressors, is a key regulator of terminal differentiation in B-lymphocytes and is critical for plasma cell differentiation.


METHODS
Here we document the expression of PRDM1 in normal and neoplastic lymphoid cells, through the use of a monoclonal antibody that recognizes the molecule in paraffin-embedded tissue sections. A large series of B and T-cell lymphomas (679 cases) was studied, using tissue microarrays.


RESULTS
Multiple myeloma, plasmacytoma and lymphoplasmacytic lymphoma cases (n=19) were positive. Plasmablastic lymphoma, oral mucosa-type (n=15), were also found to be positive. PRDM1 protein was expressed in some cases of B-cell neoplasia, i.e. chronic lymphocytic leukemia/small lymphocytic lymphoma (15%), diffuse large B-cell lymphoma (43%), classical Hodgkin's lymphoma (41%) and also in T-cell lymphoma (23%).


CONCLUSIONS
Most B-neoplastic cells showing plasmablastic differentiation were PRDM1-positive. Unexpectedly, a subset of diffuse large B-cell lymphoma expressed PRDM1, lacked detectable plasmablastic or immunoblastic changes and displayed more aggressive behavior, with a shorter failure-free survival. In contrast to normal B-cells, diffuse large B-cell lymphoma cases with increased PRDM1 expression co-expressed BCL-6 and MUM1/IRF4, confirming that PRDM1 expression in these tumors is insufficient to drive the full genetic program associated with plasmacytic differentiation.
Monoclonal Antibodies Unit, Biotechnology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain. jgarcia@cnio.es
José-Francisco
JF
Garcia
Giovanna
G
Roncador
Juan-Fernando
JF
García
Ana-Isabel
AI
Sánz
Lorena
L
Maestre
Elena
E
Lucas
Santiago
S
Montes-Moreno
Rebeca
R
Fernandez Victoria
Jorge L
JL
Martinez-Torrecuadrara
Teresa
T
Marafioti
David Y
DY
Mason
Miguel A
MA
Piris
D002454:Cell Differentiation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D016393:Lymphoma, B-Cell / Q000473:pathology*; D016399:Lymphoma, T-Cell / Q000473:pathology*; D046228:Microarray Analysis; D010950:Plasma Cells / Q000166:cytology; D000074462:Positive Regulatory Domain I-Binding Factor 1; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
D012097:Repressor Proteins; D014157:Transcription Factors; C087042:PRDM1 protein, human; D000074462:Positive Regulatory Domain I-Binding Factor 1