Based on the results of CML cell lines, the endogenous mRNA and protein levels of ABCG2 in 61 consecutive CML patients with Ph-positive metaphases and/or BCR-ABL–positive transcripts in the CP (chronic phase) and in 35 patients in AP/BP (accelerated phase/blastic phase) were detected by real-time RT-PCR and FACS analysis, respectively, at our hospital (Tab. The gene discussed is ABCG2; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.