The Raf-1 protein, a cytoplasmic serine/threonine kinase, plays an important role in signal transduction pathways. In order to examine the role of Raf-1 in human myeloid leukemia, we determined raf-1 mRNA expression by Northern blot analysis in blast cell samples from 27 acute myeloid leukemia (AML) cases and peripheral blood mononuclear cells from six healthy donors. A normal raf-1 transcript size was detected in all cases investigated. However, overexpression of raf-1 mRNA was found in 2 of 27 AML cases, both of which were erythroleukemias (AML, FAB M6).
