In a pilot phase 2 study in 46 CML patients, Mustjoki et al. [31] used cell sorting followed by fluorescence in situ hybridization (FISH) to evaluate the LSC fraction in terms of BM cells with a CD34+CD38− and Philadelphia-positive phenotype at diagnosis and at +1, +3 and +6 months from start of treatment with imatinib or dasatinib. Here, CD34 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.