PU.1 and CEBPA expression in acute myeloid leukemia.

Alterations of the transcription factors CCAAT/enhancer binding protein alpha (CEBPA) and PU.1 have been described in acute myeloid leukemia (AML). We studied CEBPA and PU.1 mRNA levels by real-time RT-PCR in 109 primary AML samples, compared with normal bone marrow and peripheral blood cells. Low PU.1 levels were observed in monoblastic leukemias, while low CEBPA levels were associated with leukopenia at diagnosis and lack of expression of differentiation antigens CD33 and CD11c. We conclude that down-regulation of CEBPA and PU.1 is not a general feature of primary AML, but appears to be restricted to distinct AML subtypes.