TKI treatment result in BMPR1b-positive CD34⁺cell accumulation in resistant patients. Follow-up of transcriptional expression of BCR-ABL (A-B) and BMPR1b (C-D) genes in BM cells from CML patients at diagnosis and in remission or resistant under TKI in MNC (A-C) or CD34⁺ (B-D) selected cells. Results from individual samples analyzed are expressed in arbitrary units, and heavy horizontal lines represent the mean values ± SEM of the indicated number of analyzed samples. (E) Absolute number of cells of CD34 or BMPR1b positive cells per milliliter of BM in TKI-resistant patients and in CCyR patients presented as individual value per patient. The heavy horizontal lines represent the mean values ± SEM of the indicated number of analyzed samples. (F) Experimental protocol: CD34⁺ cells from newly diagnosed CP patients treated or not in serum-free media with IM at 1 or 2 µM. After 5 days of culture, cells were analyzed for BMPR1b expression by flow cytometry. Data are presented as a graph that represents the percentage of mean value of BMPR1b positive cells ± SEM of five independent samples (left panel), illustrated by one representative dot plot histogram and a representation of individual values for each sample treated or not with imatinib (mean of values obtained for cells treated with 1 or 2 μM of IM) (right panel). NBM, normal bone marrow. NS, not significant (P > .05). *P ≤ .05; **P ≤ .01; ***P ≤ .001; ****P ≤ .0001.