Expression of the macrophage specific colony-stimulating factor (CSF-1) during human monocytic differentiation.

We and others have previously demonstrated expression of the co-fms proto-oncogene during human monocytic differentiation. The c-fms gene has since been shown to encode for the macrophage specific colony stimulating factor (CSF-1) receptor. The present results demonstrate that both CSF-1 and c-fms transcripts are induced during monocytic differentiation of human HL-60 leukemia cells. The results further demonstrate that normal human monocytes express CSF-1 RNA and that the level of these transcripts increases upon treatment with phorbol ester. Finally, the detection of CSF-1 RNA in HL-60 cells and in monocytes is associated with production of the CSF-1 gene product. These findings would suggest that monocytes are capable of regulating their own survival, growth and differentiation through CSF-1 production.