Advancements in genomics are transforming the clinical management of chronic myeloid leukemia (CML) toward precision medicine. The impact of somatic mutations on treatment outcomes is still under debate. We studied the association of somatic mutations in epigenetic modifier genes and activated signaling/myeloid transcription factors (AS/MTFs) with disease progression and treatment failure in patients with CML after tyrosine kinase inhibitor (TKI) therapy. A total of 394 CML samples were sequenced, including 254 samples collected at initial diagnosis and 140 samples taken during follow-up. Single-molecule molecular inversion probe (smMIP)-based next-generation sequencing (NGS) was conducted targeting recurrently mutated loci in 40 genes, with a limit of detection of 0.2%. Seventy mutations were detected in 57 diagnostic samples (22.4%), whereas 64 mutations were detected in 39 of the follow-up samples (27.9%). Carrying any mutation at initial diagnosis was associated with worse outcomes after TKI therapy, particularly in AS/MTF genes. Patients having these mutations at initial diagnosis and treated with imatinib showed higher risks of treatment failure (hazard ratio, 2.53; 95% confidence interval, 1.13-5.66; P = .0239). The adverse prognostic impact of the mutations was not clear for patients treated with second-generation TKIs. The multivariate analysis affirmed that mutations in AS/MTF genes independently serve as adverse prognostic factors for molecular response, failure-free survival, and progression risk. Additionally, there was an observable nonsignificant trend indicating a heightened risk of progression to advanced disease and worse overall survival. In conclusion, mutations in the AS/MTF genes using smMIP-based NGS can help identify patients with a potential risk of both treatment failure and progression and may help upfront TKI selection.

• MeSH
• chronická myeloidní leukemie * genetika   farmakoterapie   mortalita   diagnóza   MeSH
• dospělí MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mutace * MeSH
• prognóza MeSH
• progrese nemoci MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• signální transdukce MeSH
• transkripční faktory genetika   MeSH
• výsledek terapie MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

From the laboratory perspective, effective management of patients with chronic myeloid leukemia (CML) requires accurate diagnosis, assessment of prognostic markers, sequential assessment of levels of residual disease and investigation of possible reasons for resistance, relapse or progression. Our scientific and clinical knowledge underpinning these requirements continues to evolve, as do laboratory methods and technologies. The European LeukemiaNet convened an expert panel to critically consider the current status of genetic laboratory approaches to help diagnose and manage CML patients. Our recommendations focus on current best practice and highlight the strengths and pitfalls of commonly used laboratory tests.

• MeSH
• chronická myeloidní leukemie * diagnóza   genetika   terapie   MeSH
• inhibitory proteinkinas * MeSH
• lidé MeSH
• recidiva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• inhibitory proteinkinas * MeSH

One of the indications for BCR::ABL1 mutation testing in chronic myeloid leukemia (CML) is when tyrosine kinase inhibitor therapy (TKI) needs to be changed for unsatisfactory response. In this study, we evaluated a droplet digital PCR (ddPCR)-based multiplex strategy for the detection and quantitation of transcripts harbouring mutations conferring resistance to second-generation TKIs (2GTKIs). Parallel quantitation of e13a2, e14a2 and e1a2 BCR::ABL1 fusion transcripts enables to express results as percentage of mutation positive- over total BCR::ABL1 transcripts. We determined the limit of blank in 60 mutation-negative samples. Accuracy was demonstrated by further analysis of 48 samples already studied by next generation sequencing (NGS). Mutations could be called down to 0.5% and across 3-logs of BCR::ABL1 levels. Retrospective review of BCR::ABL1 NGS results in 513 consecutive CML patients with non-optimal response to first- or second-line TKI therapy suggested that a ddPCR-based approach targeted against 2GTKI-resistant mutations would score samples as mutation-negative in 22% of patients with warning response to imatinib but only in 6% of patients with warning response to 2GTKIs. We conclude ddPCR represents an attractive method for easy, accurate and rapid screening for 2GTKI-resistant mutations impacting on TKI selection, although ddPCR cannot identify compound mutations.

• MeSH
• bcr-abl fúzní proteiny * MeSH
• chemorezistence MeSH
• chronická myeloidní leukemie * MeSH
• inhibitory proteinkinas MeSH
• lidé MeSH
• mutace MeSH
• polymerázová řetězová reakce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bcr-abl fúzní proteiny * MeSH
• inhibitory proteinkinas MeSH

Chronic myeloid leukemia (CML)-study IV was designed to explore whether treatment with imatinib (IM) at 400 mg/day (n=400) could be optimized by doubling the dose (n=420), adding interferon (IFN) (n=430) or cytarabine (n=158) or using IM after IFN-failure (n=128). From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase were randomized into a 5-arm study. The study was powered to detect a survival difference of 5% at 5 years. After a median observation time of 9.5 years, 10-year overall survival was 82%, 10-year progression-free survival was 80% and 10-year relative survival was 92%. Survival between IM400 mg and any experimental arm was not different. In a multivariate analysis, risk group, major-route chromosomal aberrations, comorbidities, smoking and treatment center (academic vs other) influenced survival significantly, but not any form of treatment optimization. Patients reaching the molecular response milestones at 3, 6 and 12 months had a significant survival advantage. For responders, monotherapy with IM400 mg provides a close to normal life expectancy independent of the time to response. Survival is more determined by patients' and disease factors than by initial treatment selection. Although improvements are also needed for refractory disease, more life-time can currently be gained by carefully addressing non-CML determinants of survival.

• MeSH
• analýza přežití * MeSH
• chronická myeloidní leukemie farmakoterapie   terapie   MeSH
• dospělí MeSH
• imatinib mesylát terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• protinádorové látky terapeutické užití   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• transplantace hematopoetických kmenových buněk MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• randomizované kontrolované studie MeSH
• Názvy látek
• imatinib mesylát MeSH
• protinádorové látky MeSH

BACKGROUND: Through high-throughput next-generation sequencing of promoters of solute carrier and ATP-binding cassette genes, which encode drug transporters, we aimed to identify SNPs associated with the response to imatinib administered for first-line treatment of patients with chronic myeloid leukemia. METHODS: In silico analysis using publicly available databases was done to select the SLC and ABC genes and their promoters for the next-generation sequencing. SNPs associated with the imatinib response were identified using Fisher's exact probability tests and subjected to the linkage disequilibrium analyses with regulatory loci of concerned genes. We analyzed cumulative achievement of major molecular response and probability of event free survival in relation to identified SNP genotypes in 129 CML patients and performed multivariate analysis for determination of genotypes as independent predictors of outcome. Gene expression analysis of eight cell lines naturally carrying different genotypes was performed to outline an impact of genotypes on the gene expression. RESULTS: We observed significant differences in the frequencies of the rs460089-GC and rs460089-GG (SLC22A4) genotypes among rs2631365-TC (SLC22A5) genotype carriers that were associated with optimal and non-optimal responses, respectively. Loci rs460089 and rs2631365 were in highly significant linkage disequilibrium with 12 regulatory loci in introns of SLC22A4 and SLC22A5 encoding imatinib transporters. Genotype association analysis with the response to imatinib indicated that rs460089-GC carriers had a significantly higher probability of achieving a stable major molecular response (BCR-ABL1 transcript level below or equal to 0.1% in the international scale). In contrast, the rs460089-GG represented a risk factor for imatinib failure, which was significantly higher in rs460089-GG_rs2631365-TC carriers. CONCLUSIONS: This exploratory study depicted potentially important genetic markers predicting outcome of imatinib treatment, which may be helpful for tailoring therapy in clinical practice.

• Klíčová slova
• CML, Imatinib, Response, SLC,
• MeSH
• buňky K562 MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   MeSH
• genotyp MeSH
• imatinib mesylát aplikace a dávkování   terapeutické užití   MeSH
• jednonukleotidový polymorfismus * MeSH
• lidé MeSH
• mutační rychlost MeSH
• nádorové buněčné linie MeSH
• promotorové oblasti (genetika) MeSH
• proteiny přenášející organické kationty genetika   MeSH
• protinádorové látky aplikace a dávkování   terapeutické užití   MeSH
• rodina nosičů rozpuštěných látek 22, člen 5 genetika   MeSH
• sekvenční analýza DNA metody   MeSH
• symportéry MeSH
• vazebná nerovnováha MeSH
• výsledek terapie MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• imatinib mesylát MeSH
• proteiny přenášející organické kationty MeSH
• protinádorové látky MeSH
• rodina nosičů rozpuštěných látek 22, člen 5 MeSH
• SLC22A4 protein, human MeSH Prohlížeč
• SLC22A5 protein, human MeSH Prohlížeč
• symportéry MeSH

BACKGROUND: Imatinib-resistant chronic myeloid leukemia (CML) patients receiving second-line tyrosine kinase inhibitor (TKI) therapy with dasatinib or nilotinib have a higher risk of disease relapse and progression and not infrequently BCR-ABL1 kinase domain (KD) mutations are implicated in therapeutic failure. In this setting, earlier detection of emerging BCR-ABL1 KD mutations would offer greater chances of efficacy for subsequent salvage therapy and limit the biological consequences of full BCR-ABL1 kinase reactivation. Taking advantage of an already set up and validated next-generation deep amplicon sequencing (DS) assay, we aimed to assess whether DS may allow a larger window of detection of emerging BCR-ABL1 KD mutants predicting for an impending relapse. METHODS: a total of 125 longitudinal samples from 51 CML patients who had acquired dasatinib- or nilotinib-resistant mutations during second-line therapy were analyzed by DS from the time of failure and mutation detection by conventional sequencing backwards. BCR-ABL1/ABL1%(IS) transcript levels were used to define whether the patient had 'optimal response', 'warning' or 'failure' at the time of first mutation detection by DS. RESULTS: DS was able to backtrack dasatinib- or nilotinib-resistant mutations to the previous sample(s) in 23/51 (45 %) pts. Median mutation burden at the time of first detection by DS was 5.5 % (range, 1.5-17.5 %); median interval between detection by DS and detection by conventional sequencing was 3 months (range, 1-9 months). In 5 cases, the mutations were detectable at baseline. In the remaining cases, response level at the time mutations were first detected by DS could be defined as 'Warning' (according to the 2013 ELN definitions of response to 2nd-line therapy) in 13 cases, as 'Optimal response' in one case, as 'Failure' in 4 cases. No dasatinib- or nilotinib-resistant mutations were detected by DS in 15 randomly selected patients with 'warning' at various timepoints, that later turned into optimal responders with no treatment changes. CONCLUSIONS: DS enables a larger window of detection of emerging BCR-ABL1 KD mutations predicting for an impending relapse. A 'Warning' response may represent a rational trigger, besides 'Failure', for DS-based mutation screening in CML patients undergoing second-line TKI therapy.

• Klíčová slova
• BCR-ABL1, Chronic myeloid leukemia, Deep sequencing, Tyrosine kinase inhibitors, Warning,
• MeSH
• bcr-abl fúzní proteiny genetika   MeSH
• chemorezistence MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   MeSH
• farmakogenomické varianty MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• jednonukleotidový polymorfismus MeSH
• lidé MeSH
• sekvenční analýza DNA metody   MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bcr-abl fúzní proteiny MeSH
• BCR-ABL1 fusion protein, human MeSH Prohlížeč
• inhibitory proteinkinas MeSH

Identification and quantitative monitoring of mutant BCR-ABL1 subclones displaying resistance to tyrosine kinase inhibitors (TKIs) have become important tasks in patients with Ph-positive leukemias. Different technologies have been established for patient screening. Various next-generation sequencing (NGS) platforms facilitating sensitive detection and quantitative monitoring of mutations in the ABL1-kinase domain (KD) have been introduced recently, and are expected to become the preferred technology in the future. However, broad clinical implementation of NGS methods has been hampered by the limited accessibility at different centers and the current costs of analysis which may not be regarded as readily affordable for routine diagnostic monitoring. It is therefore of interest to determine whether NGS platforms can be adequately substituted by other methodological approaches. We have tested three different techniques including pyrosequencing, LD (ligation-dependent)-PCR and NGS in a series of peripheral blood specimens from chronic myeloid leukemia (CML) patients carrying single or multiple mutations in the BCR-ABL1 KD. The proliferation kinetics of mutant subclones in serial specimens obtained during the course of TKI-treatment revealed similar profiles via all technical approaches, but individual specimens showed statistically significant differences between NGS and the other methods tested. The observations indicate that different approaches to detection and quantification of mutant subclones may be applicable for the monitoring of clonal kinetics, but careful calibration of each method is required for accurate size assessment of mutant subclones at individual time points.

• Klíčová slova
• BCR-ABL1, CML, LD-PCR, NGS, pyrosequencing, quantitative analysis of mutant subclones,
• MeSH
• bcr-abl fúzní proteiny chemie   genetika   MeSH
• chronická myeloidní leukemie genetika   patologie   MeSH
• DNA analýza   genetika   metabolismus   MeSH
• lidé MeSH
• polymerázová řetězová reakce * MeSH
• sekvenční analýza DNA * MeSH
• srovnávací genomová hybridizace MeSH
• vysoce účinné nukleotidové sekvenování * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• bcr-abl fúzní proteiny MeSH
• DNA MeSH

In chronic myeloid leukemia (CML) and Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) patients who fail imatinib treatment, BCR-ABL1 mutation profiling by Sanger sequencing (SS) is recommended before changing therapy since detection of specific mutations influences second-generation tyrosine kinase inhibitor (2GTKI) choice. We aimed to assess i) in how many patients who relapse on second-line 2GTKI therapy next generation sequencing (NGS) may track resistant mutations back to the sample collected at the time of imatinib resistance, before 2GTKI start (switchover sample) and ii) whether low level mutations identified by NGS always undergo clonal expansion. To this purpose, we used NGS to retrospectively analyze 60 imatinib-resistant patients (CML, n = 45; Ph+ ALL,n = 15) who had failed second-line 2GTKI therapy and had acquired BCR-ABL1 mutations (Group 1) and 25 imatinib-resistant patients (CML, n = 21; Ph+ ALL, n = 4) who had responded to second-line 2GTKI therapy, for comparison (Group 2). NGS uncovered that in 26 (43%) patients in Group 1, the 2GTKI-resistant mutations that triggered relapse were already detectable at low levels in the switchover sample (median mutation burden, 5%; range 1.1%-18.4%). Importantly, none of the low level mutations detected by NGS in switchover samples failed to expand whenever the patient received the 2GTKI to whom they were insensitive. In contrast, no low level mutation that was resistant to the 2GTKI the patients subsequently received was detected in the switchover samples from Group 2. NGS at the time of imatinib failure reliably identifies clinically relevant mutations, thus enabling a more effective therapeutic tailoring.

• Klíčová slova
• BCR-ABL1, Next-generation sequencing, acute lymphoblastic leukemia, chronic myeloid leukemia, tyrosine kinase inhibitors,
• MeSH
• akutní lymfatická leukemie farmakoterapie   genetika   MeSH
• bcr-abl fúzní proteiny genetika   MeSH
• chemorezistence genetika   MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   MeSH
• dasatinib terapeutické užití   MeSH
• dospělí MeSH
• imatinib mesylát terapeutické užití   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutační analýza DNA metody   MeSH
• retrospektivní studie MeSH
• senioři MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bcr-abl fúzní proteiny MeSH
• BCR-ABL1 fusion protein, human MeSH Prohlížeč
• dasatinib MeSH
• imatinib mesylát MeSH
• inhibitory proteinkinas MeSH

Tyrosine kinase inhibitors represent today's treatment of choice in chronic myeloid leukemia (CML). Allogeneic hematopoietic stem cell transplantation (HSCT) is regarded as salvage therapy. This prospective randomized CML-study IIIA recruited 669 patients with newly diagnosed CML between July 1997 and January 2004 from 143 centers. Of these, 427 patients were considered eligible for HSCT and were randomized by availability of a matched family donor between primary HSCT (group A; N=166 patients) and best available drug treatment (group B; N=261). Primary end point was long-term survival. Survival probabilities were not different between groups A and B (10-year survival: 0.76 (95% confidence interval (CI): 0.69-0.82) vs 0.69 (95% CI: 0.61-0.76)), but influenced by disease and transplant risk. Patients with a low transplant risk showed superior survival compared with patients with high- (P<0.001) and non-high-risk disease (P=0.047) in group B; after entering blast crisis, survival was not different with or without HSCT. Significantly more patients in group A were in molecular remission (56% vs 39%; P=0.005) and free of drug treatment (56% vs 6%; P<0.001). Differences in symptoms and Karnofsky score were not significant. In the era of tyrosine kinase inhibitors, HSCT remains a valid option when both disease and transplant risk are considered.

• MeSH
• analýza přežití MeSH
• chronická myeloidní leukemie diagnóza   mortalita   patologie   terapie   MeSH
• dárci tkání MeSH
• dospělí MeSH
• homologní transplantace MeSH
• imatinib mesylát terapeutické užití   MeSH
• indukce remise MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• prognóza MeSH
• prospektivní studie MeSH
• protinádorové látky terapeutické užití   MeSH
• riziko MeSH
• rodina MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• transplantace hematopoetických kmenových buněk * MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• randomizované kontrolované studie MeSH
• srovnávací studie MeSH
• Názvy látek
• imatinib mesylát MeSH
• inhibitory proteinkinas MeSH
• protinádorové látky MeSH

The efficacy of therapeutic modalities in chronic myeloid leukemia (CML) depends on both genetic and epigenetic mechanisms. This review focuses on epigenetic mechanisms involved in the pathogenesis of CML and in resistance of tumor cells to tyrosine kinase inhibitors leading to the leukemic clone escape and propagation. Regulatory events at the levels of gene regulation by transcription factors and microRNAs are discussed in the context of CML pathogenesis and therapeutic modalities.

• MeSH
• bcr-abl fúzní proteiny antagonisté a inhibitory   genetika   terapeutické užití   MeSH
• chemorezistence MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   patologie   MeSH
• epigenomika * MeSH
• inhibitory proteinkinas farmakologie   terapeutické užití   MeSH
• lidé MeSH
• metylace DNA MeSH
• mikro RNA fyziologie   MeSH
• protinádorové látky farmakologie   terapeutické užití   MeSH
• regulace genové exprese u leukemie účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• bcr-abl fúzní proteiny MeSH
• inhibitory proteinkinas MeSH
• mikro RNA MeSH
• protinádorové látky MeSH