title: c-fos oncogene expression in human hematopoietic malignancies is restricted to acute leukemias with monocytic phenotype and to subsets of B cell leukemias.
abstract: To evaluate relationships between c-fos proto-oncogene expression and specific lineages of hematopoietic differentiation we analyzed the constitutive and TPA-induced expression of the c-fos gene in a wide variety of fresh human leukemic cells. High constitutive c-fos expression was detected in acute leukemias with monocytic phenotype (FAB M4/M5) and in subsets of B lymphoid leukemias, some of which coexpressed B lymphocytic and monocytic markers. Conversely, low basal levels of c-fos transcripts were found in pure acute granulocytic leukemias (FAB M1/M2/M3), in erythroleukemias (FAB M6), in the great majority of B, and in all T lymphoid leukemias. TPA-induced c-fos expression seems to correlate with monocytoid differentiation only when sustained levels of transcripts (ie, detectable for at least 24 hours) were detected. Sustained c-fos expression was in fact observed only in those myeloid or lymphoid cells that acquired a stable monocyte-like phenotype in response to the phorbol ester. These results indicate that high constitutive c-fos expression may identify myelomonocytic-oriented forms of leukemia, specific subsets of B lymphoid malignancies, and at least some cells terminally differentiated in vitro to a monocyte-like phenotype. c-fos oncogene expression can therefore be regarded as an additional marker for the subclassification of human leukemias.
mesh_terms: D000208:Acute Disease; D001402:B-Lymphocytes / Q000166:cytology*; D001853:Bone Marrow / Q000473:pathology; D002454:Cell Differentiation; D002908:Chronic Disease; D006801:Humans; D007938:Leukemia / Q000097:blood / Q000145:classification / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D000090063:Proto-Oncogene Mas; D011519:Proto-Oncogenes; D014158:Transcription, Genetic