To determine whether OLFM4 provides a survival advantage for cells more primitive than CFCs and whether it can affect the response of these cells to imatinib, we performed an LTC-IC assay using CML sCD34+ cells treated with siOLFM4, imatinib or both together. The gene discussed is OLFM4; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.