Hematopoietic growth factors (BPA and Epo) induce the expressions of c- myc and c- fos proto-oncogenes in normal human erythroid progenitors

We investigated serial expressions of eight proto-oncogenes during in-vitro differentiation of normal human burst-forming unit, erythroid (BFU-E), and found that c- myc and c- fos are expressed in progenies of BFU-E. The expressions of the two proto-oncogenes correlated to the replating efficiency and adversely to erythroid differentiation. The absence of hematopoietic growth factors decreased the expressions, but the addition of erythropoietin together with burst promoting activity induced a re-expression of the c- myc and c- fos after 2 h of incubation. These observations suggest that the c- myc and c- fos proto-oncogenes have a physiological role in the proliferation of erythroid progenitors and that activations of the two proto-oncogenes are early cellular events after the stimulation by hematopoietic growth factors.