BACKGROUND AND OBJECTIVE: The availability of different tyrosine kinase inhibitors (TKIs) with distinct anti-leukemic potency enables optimization of current therapeutic regimens; however, some patients lose their therapy response and acquire TKI resistance. In this study, we describe a single-center experience of monitoring BCR-ABL1 kinase domain (KD) mutations and discuss the impact of treatment on mutation selection. METHODS: Chronic myelogenous leukemia (CML) patients treated with TKIs at the Department of Internal Medicine-Hematology and Oncology, Masaryk University and University Hospital Brno during 2003-2011 were included in this study. A total number of 100 patients who did not achieve an optimal therapy response or who lost their therapy response were screened for the presence of BCR-ABL1 KD mutations, using direct sequencing. RESULTS: Our data show that pretreatment with non-specific non-TKI drugs prior to TKI therapy does not preferentially select for initial BCR-ABL1 KD mutations, in contrast to first-line imatinib therapy, which shows a clear predominance of T315I or P-loop mutations compared with mutations located in other KD regions. In addition, the median time to detection of P-loop mutations was substantially shorter in patients treated with first-line imatinib than in those pretreated with non-TKI drugs. Furthermore, analysis of CML patients who had recurrent resistance to TKI therapy revealed possible therapy-driven selection of BCR-ABL1 KD mutations. Finally, we confirm the previously described poor prognosis of CML patients with mutations in the BCR-ABL1 KD, since 40.0% of our CML patients who harbored a BCR-ABL1 KD mutation died from CML while receiving TKI treatment. Moreover, among the patients who are still on treatment, 27.8% have already progressed. Our data also confirm the unique position of the T315I mutation with respect to its strong resistance to currently approved TKIs. CONCLUSION: On the basis of the 'real-life' data described in this study, it is possible that the therapy itself results in its failure and selects the most resistant mutations under the selective pressure of the applied therapy regimen in some CML patients who harbor BCR-ABL1 KD mutations.

• MeSH
• Fusion Proteins, bcr-abl genetics   MeSH
• Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy   genetics   MeSH
• Adult MeSH
• Protein Kinase Inhibitors therapeutic use   MeSH
• Middle Aged MeSH
• Humans MeSH
• Mutation MeSH
• Antineoplastic Agents therapeutic use   MeSH
• Aged MeSH
• Protein-Tyrosine Kinases genetics   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Fusion Proteins, bcr-abl MeSH
• Protein Kinase Inhibitors MeSH
• Antineoplastic Agents MeSH
• Protein-Tyrosine Kinases MeSH

BACKGROUND AND OBJECTIVE: It has been shown that the occurrence of the BCR-ABL1 T315I mutation leads to a very poor therapeutic outcome in chronic myelogenous leukemia (CML) patients treated with tyrosine kinase inhibitors. Therefore, early detection of this mutation could potentially lead to early therapeutic intervention and a better prognosis with the ongoing treatment regimen. METHODS: The detection of BCR-ABL1 kinase domain (KD) mutations was performed by direct sequencing of peripheral blood (PB), total bone marrow (BM), and BM CD34+ cells from a reported CML patient. RESULTS: In this patient, the T315I mutation was detected in BM CD34+ cells 6 months prior to its emergence in PB, suggesting evolution and expansion of the T315I mutation clone, which most likely originated from more primitive CML cells. CONCLUSION: Our finding reflects the natural development of a T315I mutation within the hematopoietic system of the reported patient and indicates the importance of BCR-ABL1 mutation monitoring in more primitive cell populations. Considering the natural history of T315I development in this reported CML case, we hypothesize that BCR-ABL1 KD mutations may be pre-concentrated in more primitive CML cells, which subsequently expand into the PB. These findings may have future implications for the strategy used for detecting BCR-ABL1 mutations.

• MeSH
• Antigens, CD34 analysis   MeSH
• Fusion Proteins, bcr-abl genetics   MeSH
• Benzamides MeSH
• Bone Marrow Cells cytology   enzymology   MeSH
• Leukemia, Myelogenous, Chronic, BCR-ABL Positive blood   drug therapy   genetics   MeSH
• Hydroxyurea therapeutic use   MeSH
• Imatinib Mesylate MeSH
• Humans MeSH
• Mutation MeSH
• Piperazines therapeutic use   MeSH
• Disease Progression MeSH
• Antineoplastic Agents therapeutic use   MeSH
• Pyrimidines therapeutic use   MeSH
• Aged MeSH
• Protein-Tyrosine Kinases genetics   MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Aged MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antigens, CD34 MeSH
• Fusion Proteins, bcr-abl MeSH
• Benzamides MeSH
• Hydroxyurea MeSH
• Imatinib Mesylate MeSH
• nilotinib MeSH Browser
• Piperazines MeSH
• Antineoplastic Agents MeSH
• Pyrimidines MeSH
• Protein-Tyrosine Kinases MeSH

BACKGROUND: MicroRNAs are important regulators of transcription in hematopoiesis. Their expression deregulations were described in association with pathogenesis of some hematological malignancies. This study provides integrated microRNA expression profiling at different phases of chronic myeloid leukemia (CML) with the aim to identify microRNAs associated with CML pathogenesis. The functions of in silico filtered targets are in this report annotated and discussed in relation to CML pathogenesis. RESULTS: Using microarrays we identified differential expression profiles of 49 miRNAs in CML patients at diagnosis, in hematological relapse, therapy failure, blast crisis and major molecular response. The expression deregulation of miR-150, miR-20a, miR-17, miR-19a, miR-103, miR-144, miR-155, miR-181a, miR-221 and miR-222 in CML was confirmed by real-time quantitative PCR. In silico analyses identified targeted genes of these miRNAs encoding proteins that are involved in cell cycle and growth regulation as well as several key signaling pathways such as of mitogen activated kinase-like protein (MAPK), epidermal growth factor receptor (EGFR, ERBB), transforming growth factor beta (TGFB1) and tumor protein p53 that are all related to CML. Decreased levels of miR-150 were detected in patients at diagnosis, in blast crisis and 67% of hematological relapses and showed significant negative correlation with miR-150 proved target MYB and with BCR-ABL transcript level. CONCLUSIONS: This study uncovers microRNAs that are potentially involved in CML and the annotated functions of in silico filtered targets of selected miRNAs outline mechanisms whereby microRNAs may be involved in CML pathogenesis.

• MeSH
• Molecular Sequence Annotation MeSH
• Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics   physiopathology   MeSH
• Down-Regulation genetics   MeSH
• Genes, myb genetics   MeSH
• Humans MeSH
• MicroRNAs genetics   metabolism   MeSH
• Gene Expression Regulation, Leukemic * MeSH
• Reproducibility of Results MeSH
• Cluster Analysis MeSH
• Gene Expression Profiling MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• MicroRNAs MeSH
• MIRN150 microRNA, human MeSH Browser

In recent years, several independent prognostic factors in cytogenetically normal acute myeloid leukemia (CN-AML) have been reported. Mutations or the expression levels of certain genes have been often used as molecular markers for prediction of a patient's outcome or for evaluation of treatment outcome. One of them, the gene encoding CCAAT/enhanced binding protein alpha (CEBPA), plays an important role in myeloid differentiation and, when mutated, confers a favorable prognosis for patients with CN-AML. Complete mutation screening of the CEBPA gene is therefore beneficial and requires fast, precise, and sensitive diagnostic tools. Thus, for routine diagnostics, we developed a screening method using high-resolution melt curve analysis prior to direct sequencing, where only positive samples (according to reference) are further sequenced. With this approach, all positive and negative patients were successfully distinguished, and the results obtained were in absolute concordance with the direct sequence analysis.

• MeSH
• Nucleic Acid Denaturation MeSH
• Humans MeSH
• Molecular Sequence Data MeSH
• Mutation genetics   MeSH
• DNA Mutational Analysis methods   MeSH
• CCAAT-Enhancer-Binding Protein-alpha genetics   MeSH
• Base Sequence MeSH
• Transition Temperature MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• CCAAT-Enhancer-Binding Protein-alpha MeSH