Myeloid progenitors isolated from Fancc^-/- mice retain IFN-γ hypersensitivity following IFN-γ treatment in vivo. IFN-γ sensitivity of myeloid progenitors from WT and Fancc^-/- mice was assessed 90 and 180 days following in vivo treatment with IFN-γ or vehicle control. From each day of evaluation, cells from 4 IFN-γ-treated or vehicle control-treated WT and Fancc^-/- mice were cultured for the growth of granulocyte-macrophage progenitors in methylcellulose at the indicated concentrations of IFN-γ. Each condition was plated in triplicate and scored on day 7 of culture. The mean data at days 90 and 180 following treatment are shown. Error bars represent SEM.