EXPRESSION OF THE C-FES PROTOONCOGENE IN GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR-DEPENDENT ACUTE MYELOGENOUS LEUKEMIA-CELLS GROWN AUTONOMOUSLY

In the present article, we show that 6 of 69 acute myelogenous leukemia (AML) samples exhibited autonomous in vitro growth that was dependent on endogenous granulocyte-macrophage colony-stimulating factor (GM-CSF). Cytoplasmic RNA harvested from all 6 leukemia specimens contained GM-CSF transcripts easily detectable by mRNA hybridization. All 6 GM-CSF-expressing leukemia samples simultaneously displayed high levels of transcripts for the c-fes proto-oncogene previously shown to be expressed in GM-CSF sensitive myeloid cells, whereas only 2 of the 48 AML samples not expressing GM-CSF accumulated c-fes mRNA. Seven of additional 14 GM-CSF-expressing specimens showed specific signals upon RNA hybridization with the c-fes probe, but failed to grow autonmously. These results suggest that c-fes and GM-CSF genes may be coordinately regulated in AML blasts and that GM-CSF-mediated growth autonomy may be linked to c-fes expression.