Expression of Granulocyte Colony-Stimulating Factor Receptor (G-CSFR) and Clinical Correlates in Acute Leukemia

Background : Granulocyte colony-stimulating factor (G-CSF) is commonly used to reduce leukopenic period during treatment of malignancy including acute leukemia. Leukemic blasts expressing granulocyte colony-stimulating factor receptor (G-CSFR) were reported and also may proliferate in response to therapeutic administration of G-CSF. However, it is not clear whether G-CSFR expression on leukemic blasts is related to clinical outcome such as leukocyte recovery or leukemia relapse. Current study evaluated expression of G-CSFR in acute leukemia and correlated with hematologic and clinical parameters. Methods : Peripheral blood or bone marrow aspirate was evaluated from 20 patients with acute myelogenous leukemia (AML) and 10 with acute lymphoblastic leukemia (ALL), 2 with acute undifferentiated leukemia (AUL), 1 with acute biphenotypic leukemia (ABL), 1 with acute mixed-lineage leukemia (AMLL). G-CSFR expression was analyzed using flow cytometry and was correlated with immunophenotype and response for chemotherapy. Results : More than 20% of blasts were positive for G-CSFR in 65% (13/20) of AML, 40% (4/10) of ALL, and all negative in ABL, AMLL, and AUL. Except that all 6 monocytic lineage leukemias (M4, M5) and all three cases of ALL with CD33 expression were positive, no consistent correlation was observed among G-CSFR expression pattern, type of acute leukemia, response to induction therapy and relapse (P>0.05). Conclusion : Current study revealed G-CSFR was expressed on not only myelogenous leukemic cells but also lymphoid ones. Although our data suggest G-CSFR expression does not affect therapeutic outcome, it remains to be determined whether G-CSF therapy is safe in G-CSFR-positive acute leukemia.