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Background: Asciminib is a novel drug specifically targeting ABL myristoyl pocket in the ABL1 protein., Methods: Forty one patients with chronic myeloid leukemia treated with asciminib from 2018 to 2022 were reviewed and analyzed for the efficacy and tolerability of asciminib using real-world experience data., Results: The median age was 60 years (range 17-90) with a past history of a cardiovascular event in 21 patients (51%). Patients were pretreated with a median of 3 previous tyrosine kinase inhibitors (range 1-5). After a median of 12 months of asciminib (range 3-41), major molecular response (MMR) rate was 39% (n = 11/28) and 42% (n = 5/12) at 6 and 12 months, respectively. Molecular response with 2 log reduction (MR2) was noted in 54% (n = 15/28) and 50% (n = 6/12) at 6 and 12 months. The cumulative incidence of MMR and MR2 was 46.3% and 66% at 12 months. Five patients discontinued asciminib due to treatment failure (n = 3) or thrombocytopenia (n = 2). There were no cardiovascular events. Out of 7 patients treated with high dose asciminib for T315I mutation, 5 patients achieved MMR or deeper response. The event-free survival was 63% at 12 months., Conclusion: This study confirmed clinical efficacy and tolerability of asciminib with real-world experience., Competing Interests: Declaration of Competing Interest FK provides consultancy for Novartis, SC provides consultancy and has honoraria for Novartis, Pfizer, BMS, Celgene, Incite. AX, NF and LB has honoraria from Novartis. BL provides consultancy, has honoraria and on the advisory board for Novartis, Pfizer, BMS, Abbvie, and AMGEN. RK is on the advisory boards of Sanofi, FORUS Therapeutics, Belgene, Pfizer and has honoraria from Janssen and BMS. SA gets research funding from Novartis and has consultancy/ honoraria from Genentech/Roche, Astra Zeneca, Novartis, BMS, Jazz, Gilead, Amgen, Beigene, Abbvie, Paladin. DK is a consultant, has received research funding, and honoraria from Pfizer, Sanofi, Paladin, and Novartis. The remaining authors have no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Currently used treatment of CML dramatically improved the prognosis of disease. However, additional chromosome aberrations (ACA/Ph+) are still one of the adverse prognostic factors., Objectives: evaluation of the impact of ACA/Ph+ appearance during disease outcome on the response to treatment. THE STUDY GROUP: consisted of 203 patients. The median time of follow-up was 72 months. ACA/Ph+ was found in 53 patients., Results: patients were divided into four groups: standard risk, intermediate, high and very high risk. When ACA/Ph+ presence was documented at diagnosis time the optimal response was observed in 41.2%, 25%, and 0% of pts with intermediate, high and very high risk, respectively. If ACA/Ph+ were detected during imatinib treatment the optimal response was in 4.8% of patients. The risk of blastic transformation for patients with standard risk, intermediate, high and very high risk was 2.7%, 18.4%, 20% and 50%, respectively., Conclusions: the presence of ACA/Ph+ at diagnosis time or their appearance on therapy seems to be clinically relevant not only in terms of the risk of blastic transformation but also in terms of the treatment failure. Gathering patients with various karyotypes and their responses to treatment would allow to set better guidelines and predictions., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Use of the potent tyrosine kinase inhibitor imatinib as the first-line treatment in chronic myeloid leukemia (CML) has decreased mortality from 20% to 2%. Approximately 30% of CML patients experience imatinib resistance, however, largely because of point mutations in the kinase domain of the BCR-ABL1 fusion gene. The aim of this study was to use next-generation sequencing (NGS) to identify mutations related to imatinib resistance. The study included 22 patients diagnosed with CML and experiencing no clinical response to imatinib. Total RNA was used for cDNA synthesis, with amplification of a fragment encompassing the BCR-ABL1 kinase domain using a nested-PCR approach. Sanger and NGS were applied to detect genetic alterations. HaplotypeCaller was used for variant calling, and STAR-Fusion software was applied for fusion breakpoint identification. After sequencing analysis, F311I, F317L, and E450K mutations were detected respectively in three different participants, and in another two patients, single nucleotide variants in BCR (rs9608100, rs140506, rs16802) and ABL1 (rs35011138) were detected. Eleven patients carried e14a2 transcripts, nine had e13a2 transcripts, and both transcripts were identified in one patient. One patient had co-expression of e14a2 and e14a8 transcripts. The results identify candidate single nucleotide variants and co-expressed BCR-ABL1 transcripts in cellular resistance to imatinib., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Life expectation of chronic myeloid leukemia patients in the tyrosine kinase inhibitors era is almost equal to that of healthy subjects. On the other hand, their long-term management must take into account a higher risk of adverse events, at least partly related to the treatment. Various studies reported a higher incidence of cardiovascular events in these patients. Clonal hematopoiesis is broadly considered a major independent risk factor for cardiovascular events. Of note, the underlying physiopathological mechanisms connect clonal hematopoiesis with a global proinflammatory status, triggering a vicious circle in which the somatic mutations and inflammation feed each other. All this considered, we investigated the occurrence of clonal hematopoiesis in chronic myeloid leukemia patients developing a cardiovascular event under tyrosine kinase inhibitor therapy., Competing Interests: Conflict of Interests The authors declare no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Philadelphia chromosome-positive acute myeloid leukemia (Ph+ AML) is a provisional disease entity in the 2016 WHO classification, while its genetic profile of Ph+ AML remains poorly defined. In addition, the differentiating features of Ph+ AML and chronic myeloid leukemia in myeloid blast crisis (CML-MBC) remain controversial., Methods: We conducted a retrospective study of 15 Ph+ AML patients to compare their clinical and laboratory profiles with 27 CML-MBC patients., Results: Compared to CML-MBC, Ph+ AML patients presented with significantly higher peripheral WBC count and bone marrow blast percentage. The immunophenotypic profiles were largely similar between Ph+ AML and CML-MBC, except for CD4 expression, which was significantly enriched in CML-MBC. Ph+ AML patients less frequently harboured co-occurring additional cytogenetic abnormalities (ACA) compared to CML-MBC, and trisomy 19 (23%) and IDH1/2 (46%) were the most common ACA and mutated genes in Ph+ AML, respectively. Overall survival (OS) did not significantly differ between Ph+ AML and CML-MBC. Ph+ AML without CML-like features appeared to have a better outcome compared to Ph+ AML with CML-like features; ACA in Ph+ AML may confer an even worse prognosis., Conclusions: Our results indicate that patients with Ph+ AML share similar genetic profiles and clinical outcomes with those with CML-MBC, thus should be classified as a high-risk entity., Competing Interests: Conflict of interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Long noncoding RNAs (lncRNAs) are identified as key players in the initiation, development, and prognosis of chronic myeloid leukemia (CML). Some lncRNAs are expected to serve as diagnostic biomarkers, predictors of clinical outcomes and therapeutic targets. We aimed to examine the expression of lncRNA colon cancer-associated transcript 2 (CCAT2) in CML patients, as well as to correlate CCAT2 expression with response to imatinib therapy. 43 newly diagnosed patients with chronic phase CML were included, and 30 healthy persons were selected as controls. Real-time reverse transcription PCR was performed to analyze the expression of CCAT2 in peripheral blood mononuclear cells. Our results reported for the first time the upregulated expression of CCAT2 in CML patients as compared with controls (P < 0.001). We demonstrated significant association between CCAT2 expression and therapy response at 3 months, and at 6 months (P = 0.004, and P = 0.005; respectively). Moreover, CCAT2 expression was significantly associated with spleen size (P = 0.006) and EUTOS sore (P = 0.030). LncRNA CCAT2 is highly expressed in the peripheral blood of CML patients, and the enhanced expression at diagnosis is linked to imatinib resistance. CCAT2 is expected to become a reliable molecular marker for predicting imatinib response in chronic phase CML patients., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Genetic differences may be associated with the response to tyrosine kinase inhibitor (TKI) in patients with chronic myeloid leukemia (CML). In this study, we identified genetic alterations between rapid and slow responders (BCR/ABL1 International Scale at 6 months: ≤0.1 % vs. > 0.1 %) of TKI treatment in chronic phase CML patients. Our analyses involved single nucleotide polymorphism (SNP), a Genome Wide Association Study and a Network-wide Association Study (NetWAS). Seventy-two patients from 16 institutions were enrolled and treated with a TKI, nilotinib. Gene Set Analysis identified genetic alterations in pathways related to the differentiation, proliferation, and activity of various innate immune cells. The NetWAS analysis found that genes associated with natural killer (NK) cells (PTPRCAP, BLNK, HCK, ARHGEF11, GPR183, TRPV2, SHKBP1, CD2) showed significant differences between rapid and slow responders of nilotinib. However, we found no significantly different genetic alterations according to the response in the SNP analysis. In conclusion, we found that rapidity of response to TKI was associated with pathway-associated genetic alterations in immune cells, particularly with respect to NK cell activity. These results suggested that the innate immune system at initial diagnosis had an important role in treatment response in patients with CML., (Copyright © 2022. Published by Elsevier Ltd.)

To compare the clinical significance of 3-month cytogenetic and molecular monitoring, we analyzed 1,410 paired cytogenetic and molecular data from 705 chronic-phase chronic myeloid leukemia patients. Based on early cytogenetic response (ECyR, Ph+≤35 %) and molecular response (EMR, BCR-ABL1 IS ≤10 %) at 3 months, the patients were divided into four groups (group 1: ECyR + EMR, n = 560; group 2: no ECyR + EMR, n = 27; group 3: ECyR + no EMR, n = 55; group 4: no ECyR + no EMR, n = 63). By 10 years, major molecular response (MMR), deep molecular response (MR4.5), overall survival (OS), and progression-free survival (PFS) rates were significantly high in group 1 (P < 0.001). Comparing groups 2 and 3, the MMR (P = 0.096), MR4.5 (P = 0.945), OS (P = 0.832), and PFS (P = 0.627) rates tended to be higher in group 2, although not significantly. Thus, the cytogenetic assay can not only be useful but its addition may also provide a more precise prediction of MR4.5., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Variant Philadelphia (Ph) translocations involving chromosome 7 are rarely seen in Chronic Myeloid Leukemia (CML) patients. It is aimed to contribute new cases to the literature by reviewing the cases in our archive and shed light into the understanding of the role of chromosome 7 in CML. This study was carried out in 237 newly diagnosed CML patients with variant Ph translocations. Among the patients, those with variant Ph translocation involving chromosome 7 were evaluated in terms of clinical and genetic characteristics. Chromosome analysis was performed on 24 and 48 h of bone marrow cultures. FISH analysis was performed with BCR-ABL1 dual color dual fusion translocation probes. BCR-ABL1 transcript levels were analysed by QRT-PCR and results were reported as BCR-ABL1/ABL1 (BCR-ABL1 (IS) %) according to international scale. Four of the patients had variant Ph translocations including chromosome 7. The karyotypes were 46,XX,t(7;9;22)(p13;q34;q11); 46,XX,t(7;9;22)(p21;q34;q11); 46,XX,t(7;9;22)(q22;q34;q11) and 46,XY,t(7;9;22)(q22;q34;q11). The breakpoints demonstrated by cytogenetic analysis were confirmed by FISH analysis. Monitoring by QRT-PCR showed that patients with variant Ph translocation including 7p13 and 7p21 had a dramatic decrease in BCR-ABL1 levels resulting in complete hematological, complete cytogenetic and deep molecular responses. Despite achieving complete hematological, complete cytogenetic response in two patients with variant Philadelphia translocation, including 7q22, no major molecular response was achieved and both patients are still in the warning category. Response to tyrosine kinase inhibitör therapy may be associated with both the variant translocation mechanism and new gene interactions that occur due to the breakpoints of additional chromosomes involved in translocation., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Ultra-deep sequencing detects low-frequency genetic mutations with high sensitivity. We used this approach to prospectively examine mutations in the BCR/ABL1 tyrosine kinase from patients with newly diagnosed, chronic-phase chronic myeloid leukemia (CML) treated with the tyrosine kinase inhibitor nilotinib. Between May 2013 and November 2014, 50 patients from 18 institutions were enrolled in the study. We screened 103 somatic mutations and found that mutations in the P-loop domain were the most frequent (173/454 mutations in the P-loop) and noted the presence of the V299 L mutation (dasatinib-resistant/nilotinib-sensitive) in 98 % of patients (49/50). No patients had Y253H, E255 V, or F359 V/C/I mutations, which would recommend dasatinib rather than nilotinib treatment. The S417Y mutation was associated with lower achievement of a major molecular response (MMR) at 6 months, and the V371A mutation was associated with reduced MMR and MR 4.5 durations (MMR for 2 years: 100 % for no mutation vs. 75 % for mutation, P=0.039; MR 4.5 for 15 months: 94.1 % vs. 25 %, P=0.002). Patients with known nilotinib-resistant mutations had lower rates of MR 4.5 achievement. In conclusion, ultra-deep sequencing is a sensitive method for genetic-based treatment decisions. Based on the results of these mutational analyses, nilotinib treatment is a promising option for Korean patients with CML., (Copyright © 2021. Published by Elsevier Ltd.)

Background: Drug resistance mechanisms are the regulatory factors associated with drug metabolism and drug transport to inward and outward of the target cells. Maybridge fragment (MBF) library is a collection of pharmacophore rich compounds having affinity with membrane transporters. This study has been designed to evaluate the efficacy of MBFs in overcoming the leukemic cells' resistance to imatinib., Methods: Imatinib resistant cells (K562-R) were prepared using myelogenous leukemia cell line (K562) by titration method. The four MBFs were prioritized for determining their effect on imatinib resistance. The cells were treated with imatinib and MBFs and the MTT assay was performed to evaluate the efficacy of MBFs in enhancing the imatinib mediated cell death. The transcript levels of Bcr-Abl1 gene and efflux transporter genes were determined by RT-qPCR analysis., Results: The MBFs enhanced the imatinib mediated cell death of K562-R cells. There was also a significant decrease in the mRNA levels of the major drug efflux genes (ABCB1, ABCB10, ABCC1 and ABCG2) when treated with a combination of imatinib and MBF in comparison to imatinib treatment alone., Conclusion: The drug efflux is one of the mechanisms of multidrug resistance in cancer cells and the MBFs used in this study were all found to significantly overcome the imatinib resistance by limiting the expression of efflux genes. This study, therefore, highlights the potential of Maybridge compounds in treating the drug resistant leukemia., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Chronic Myeloid Leukemia (CML) is characterized by the overproduction of BCR-ABL, a tyrosine kinase with constitutive activity, in which the majority of CML patients have e13a2 or e14a2 transcripts. Reckoned the possible associations between the hematologic and molecular features of the disease, a profound understanding of different aspects of this neoplasm would be provided., Method: The authors implemented a systematic literature search, utilizing the terms published articles or internationally accepted abstracts from PubMed, Embase, Medline, Cochrane library before January 2019. Weighted mean proportion and 95 % confidence intervals (CIs) of CML prevalence calculated using a fixed-effects and a random-effects model. Statistical heterogeneity was evaluated using the I2 statistic., Results: 34 studies for a total of 54,034 Patients were selected and included in the review. Results revealed that compared to e13a2 group, the overall estimated prevalence is much higher in the e14a2 (39 % and 54 %, respectively). Besides, the overall estimated prevalence ratio of male to female was higher in the e13a2 group in comparison to e14a2 (1.08 and 0.856 respectively). The overall estimated prevalence of dual transcription of e13a2/e14a2 was 1.11 %, and male/female overall estimated prevalence ratio was 1.18., Conclusion: This meta-analysis of CML patients demonstrated the e14a2 as the more common transcript type. Usually, the e14a2 transcript is prevalent in females, whereas e13a2 and dual transcription of e13a2/e14a2 are more common in men. These data explicate that the differences in proportion are not by chance. This is crucial, as the transcript type is a variable suspected to be of prognostic importance for the treatment-related response, the outcome of treatment, and the rate of treatment-free remission., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Asciminib is a potent, orally bioavailable, investigational drug that specifically and potently inhibits the tyrosine kinase activity of native ABL1, together with that of the chimeric BCR-ABL1 oncoprotein which causes chronic myeloid leukemia (CML). In contrast to ATP-competitive BCR-ABL1 kinase inhibitors employed to treat CML that target multiple kinases, asciminib binds to the myristate binding pocket on the kinase domains of ABL1 and BCR-ABL1. Hitherto no drugs have been developed whose mechanism of action involves interacting with myristate binding pockets on proteins, and analysis of the structures of such binding sites in proteins other than ABL1/ABL2/BCR-ABL1 strongly suggest that asciminib will not bind to these with high affinity. Accordingly, the drug has no known safety liabilities resulting from any off-target activity, as illustrated by its specificity towards cells expressing BCR-ABL1 and lack of effects on non-kinase targets in biochemical screens. Because asciminib does not bind to the ATP-binding site it maintains substantial activity against kinase domain mutations that impart acquired drug resistance to ATP-competitive drugs. However, in vitro studies in cells have identified BCR-ABL1 mutations that reduce the anti-proliferative activity of asciminib, some of which are associated with clinical resistance towards the drug in patients. Here we review effects of asciminib on mutant forms of BCR-ABL1, analyse their sensitivity towards the drug from a structural perspective and affirm support for employing combinations with ATP-competitive inhibitors to impede the reactivation of BCR-ABL1 kinase activity in patients receiving monotherapy., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Expression of the p210 BCR/ABL1 fusion protein has been described in virtually all patients with chronic myelogenous leukemia (CML). Previous studies have identified a guanine nucleotide exchange factor (RhoGEF) domain within BCR that is retained in p210 BCR/ABL1. Missense mutations at residues T654 (T654K) and F547 (F547L) within this domain have been reported in a CML patient in blast crisis (BC). In this study, we have evaluated p210 BCR/ABL1 constructs that contain these substitutions in a murine bone marrow transplantation (BMT) model of CML. The mutants exhibit normal expression and tyrosine kinase activity but altered signaling. When examined in the BMT assay, mice that express the mutants exhibit earlier onset of disease but have significantly extended lifespans relative to mice that express unmodified p210 BCR/ABL1. While mice that express p210 BCR/ABL1 exhibit neutrophilia that progresses to a less differentiated phenotype at death, disease in the mutant mice is characterized by eosinophilia with no maturation arrest. This observation was confirmed in vitro using myeloid cells and was associated with enhanced p53 phosphorylation and G1/S arrest. These results suggest that residues within the RhoGEF domain of p210 BCR/ABL1 can influence disease progression., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The tyrosine kinase inhibitors (TKIs) have revolutionized the management of chronic myeloid leukemia (CML) and BCR-ABL1 inhibitors form the mainstay of CML treatment. Although patients with CML generally do well under TKI therapy, there is a subgroup of patients who are resistant and/or intolerant to TKIs. In these group of patients, there is the need of additional treatment strategies. In this review, we provide an update on the current knowledge of these novel treatment approaches that can be used alone and/or in combination with TKIs., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The BCR-ABL fusion gene (BCR-ABL) has different subtypes such as p210 and p190 with p190 appear to lead to a worse prognosis. To explore the mechanism of difference in pathogenesis and prognosis in different BCR-ABL subtype-related leukemia, expression profile microarray analysis was conducted between p190 and p210 patients and verified by RT-PCR. The p21-activated kinase (PAK1) gene was chosen and regulation of the PAK1-STAT5 biological axis and its influence on proliferation and apoptosis in leukemia cells were also analyzed. The results showed that PAK1 might be an important molecular mechanism of the pathogenic difference between different BCR-ABL subtypes. In P210 (+) chronic myelogenous leukemia (CML), down-regulated PAK1 gene expressions may lead to the suppression of cell proliferation and promotion of apoptosis through phosphorylation of STAT5, with a reverse effect in P190 (+) acute lymphoblastic leukemia(ALL), especially acute B lymphoblastic leukemia (B-ALL). Additionally, in P210 (+) CML, down-regulated PAK1 expression may enhance the effect of TKI, whereas the reverse is true in P190 (+) B-ALL, demonstrating that PAK1 might also be an important therapeutic target between different BCR-ABL subtypes., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In chronic myeloid leukemia (CML), resistance against second-generation tyrosine kinase inhibitors (TKI) remains a serious clinical challenge, especially in the context of multi-resistant BCR-ABL1 mutants, such as T315I. Treatment with ponatinib may suppress most of these mutants, including T315I, but is also associated with a high risk of clinically relevant side effects. We screened for alternative treatment options employing available tyrosine kinase inhibitors (TKI) in combination. Dasatinib and bosutinib are two second-generation TKI that bind to different, albeit partially overlapping, spectra of kinase targets in CML cells. This observation prompted us to explore anti-leukemic effects of the combination dasatinib + bosutinib in highly resistant primary CML cells, various CML cell lines (K562, K562R, KU812, KCL22) and Ba/F3 cells harboring various BCR-ABL1 mutant-forms. We found that bosutinib synergizes with dasatinib in inducing growth inhibition and apoptosis in all CML cell lines and in Ba/F3 cells exhibiting BCR-ABL1 T315I . Clear synergistic effects were also observed in primary CML cells in all patients tested (n = 20), including drug-resistant cells carrying BCR-ABL1 T315I . Moreover, the drug combination produced cooperative or even synergistic apoptosis-inducing effects on CD34 + /CD38 - CML stem cells. Finally, we found that the drug combination is a potent approach to block the activity of major additional CML targets, including LYN, KIT and PDGFRα. Together, bosutinib and dasatinib synergize in producing anti-leukemic effects in drug-resistant CML cells. Whether such cooperative TKI effects also occur in vivo in patients with drug-resistant CML, remains to be determined in forthcoming studies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

To analyze the pattern of multiple mutations detected by Sanger sequencing (SS), we performed subcloning sequencing using 218 samples from 45 patients with tyrosine kinase inhibitor resistant chronic myeloid leukemia. At the first time of multiple mutation detection by SS (baseline), a total of 19 major mutations from 45 samples were detected; these mutations were found in the following order: T315I (68.9%), E255 K (33.3%), Y253H (13.3%), G250E (13.3%), and F317 L (11.1%). Subcloning sequencing of 900 baseline colonies identified 556 different mutant types, and 791 among the 900 were colonies with major mutations (87.9%). The mutations were found in the following order: T315I (36.4%), E255 K (16.2%), Y253H (7.0%), G250E (6.7%), M351 T (6.6%), and E255 V (5.3%). In subcloning sequencing with 4357 colonies of 218 serial samples, 2506 colonies (57.5%) had compound mutations, among which 2238 colonies (89.3%) had at least one major mutation. The median number of mutations in compound mutant colonies was 2 (range, 2-7), and most were double (52.9%) or triple (28.7%) mutations. Additionally, some mutations in allosteric binding sites were detected as low level mutation in 13 patients. With the available retrospective samples before baseline, subcloning sequencing identified low-level mutations of various frequencies (median, 10%) to be major mutations in 20 patients. Thus, compound mutations involving T315I and P-loop mutations were the major components of multiple mutations, and some low-level mutations with potential clinical significance were detected by subcloning sequencing. Hence, more sensitive sequencing assays are needed in patients with multiple mutations., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Tyrosine kinase inhibitors have achieved unprecedented efficacy in the treatment of chronic myeloid leukemia (CML); however, imatinib resistance has emerged as a major problem in the clinic. Because the overexpression of BCR-ABL1 critically contributes to CML pathogenesis and drug resistance, targeting the regulation of BCR-ABL1 gene expression may be an alternative therapeutic strategy. In this study, we found that the transcriptional repressor MXD1 showed low expression in CML patients and was negatively correlated with BCR-ABL1. Overexpression of MXD1 markedly inhibited the proliferation of K562 cells and sensitized the imatinib-resistant K562/G01 cell line to imatinib, with decreased BCR-ABL1 mRNA and protein expression. Further investigation using reporter gene analysis showed that MXD1 significantly inhibited the transcriptional activity of the BCR-ABL1 gene promoter. Taken together, these data show that MXD1 functions as a negative regulator of BCR-ABL1 expression and subsequently inhibits proliferation and sensitizes CML cells to imatinib treatment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The majority of patients with TKI failure respond to HCT. However, the relapse risk remains high. This study has evaluated transplant outcomes in 223 CML patients with TKI failure due to resistance (n = 132) or intolerance (n = 29), as well as those that were TKI naïve/responding with advanced disease (n = 35) or with chronic phase (CP, n = 27). We studied outcomes according to post-transplant BCR-ABL transcript level within 3 months. With respect to transplant outcomes according to the post-transplant BCR/ABLtranscript level within 3 months, the group failing to achieve a 1.3 log reduction (n = 14, 12.4%) showed the highest relapse rate of 78.6% at 5 years, compared to 26.2% and 24.1% in the groups achieving 1.3-4.0 log reduction (n = 45, 39.8%), and ≥4.1 log reduction (n = 54, 47.8%) respectively (p < 0.001). Multivariate analysis confirmed that the group failing to achieve a 1.3 log reduction had a 2.3-fold higher risk of death and 6.6 times higher risk of relapse. Poor overall survival after HCT was associated with advanced disease at diagnosis, but not disease status prior to HCT. Of 61 patients who relapsed after HCT, 47 were treated with post-transplant TKI therapy; those receiving TKI after loss of MR2 or MMR showed higher rates of response and survival compared to those receiving TKI after hematologic relapse (p < 0.001). QPCR log reduction level within 3 months post transplantation is prognostic in this population., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A retrospective study was performed to describe molecular responses (MR) on the international scale (IS) in patients with chronic myeloid leukemia (CML) treated with imatinib in routine clinical practice in Belgium and to identify patients potentially eligible for treatment discontinuation. The analysis included 116 patients with CML in chronic phase at treatment centers sending blood samples for molecular follow-up to a single EUTOS-certified laboratory. IS MR from the last patient visit between October 2014 and April 2015 were retrospectively collected. Most patients (93.1%) had an IS MR corresponding to an optimal response per European LeukemiaNet 2013 guidelines; 53.4% (62/116) of patients were in deep molecular responses ≥MR 4.5 at their last visit (mean treatment duration: 91.0 months) among whom 36.2% (42/116) had been receiving imatinib for >5.8 years and 26.7% (31/116) for >8 years (margins of error: 8.74% and 8.05%, respectively). These patients would likely have the highest chance of staying in treatment-free remission (TFR) upon discontinuation, based on published TFR trial data. Although our study only provides a snapshot in time of a patient's last MR reported, without precise information regarding MR duration, the study settings could nevertheless support the feasibility of attempting TFR outside clinical trials in the future., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

We analyzed the clinical responses to thyrosine kinase inhibitors (TKIs) and the molecular and cytogenetic characteristics of 18 chronic myeloid leukemia (CML) patients with 3-way chromosomal translocations. The patients were 14 men and 4 women, aged 23-75 years (median 57 years). The Sokal risk was low in 12 patients, intermediate in 4 patients, and high in 2 patients. Newly identified translocation breakpoints were seen in 7 of the 18 patients. Three patients had the same breakpoints of t(9;22;11)(q34;q11.2;q23). The best responses to TKIs were partial cytogenic response (PCyR) in 2 patients, complete cytogenic response (CCyR) in 3 patients, molecular response (MR) 3.0 in 7 patients, MR 4.0 in 3 patients, and MR 4.5 or higher in 3 patients. A total of 66.7% of patients did not achieve MR 4.0 or higher. In 3 patients in whom TKIs resulted in MR 4.5 or higher for more than 2 years, TKI treatment was discontinued. However, all of them exhibited a loss of MR3.0, at 2, 6, and 20 months after the discontinuation of treatment, respectively, and TKI treatment needed to be restarted. According to Kaplan-Meier survival curve analysis, the overall survival (OS) was 100 months in 56% of the patients. The 60-months cumulative incidences of CCyR, MR3.0, MR4.0 and MR4.5 were 88.9%, 72.2%, 33.3%, and 16.7%, respectively. In the 11 analyzable patients, the BCR-ABL1 mRNA subtype was e14a2 type in 4 patients and e13a2 type in 7 patients., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The human leukocyte antigen-G (HLA-G) gene encodes a tolerogenic protein known to promote tumor immune-escape. We investigated HLA-G polymorphisms and soluble molecules (sHLA-G) in 68 chronic myeloid leukemia (CML) patients. Patients with G*01:01:01 or G*01:01:02 allele had higher value of sHLA-G compared to G*01:01:03 (109.2±39.5 vs 39.9±8.8 units/ml; p=0.03), and showed lower event free survival (EFS) (62.3% vs 90.0%; p=0.02). The G*01:01:03 allele was associated with higher rates and earlier achievement of deep molecular response (MR) 4.5 (100% vs 65%, median of 8 vs 58 months, p=0.001). HLA-G alleles with higher secretion of sHLA-G seem associated with lower EFS, possibly because of an inhibitory effect on the immune system. Conversely, lower levels of sHLA-G promoted achievement of MR 4.5 , suggesting increased cooperation with immune system., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Tyrosine kinase inhibitors (TKI) constitute the frontline treatment for chronic myeloid leukemia patients. Dasatinib, a second-generation TKI, was developed to overcome TKI resistances. However, dasatinib resistances are also described but remain less characterized. To mimic in vivo acquired dasatinib resistance, the BCR-ABL1-positive cell line K562 was transiently treated with a pharmacological concentration of dasatinib, for a short time in the presence of stem cell factor. A dasatinib resistant counterpart (K562 RES) was developed. Investigation of resistance mechanisms using kinase substrate arrays revealed that FYN was overactivated in K562 RES. The FYN inhibitor KX2-391 cooperated with dasatinib to block K562 RES proliferation. Cell tracking experiments showed that activated FYN support cell proliferation independently of BCR-ABL1 in K562 RES cells. Moreover, the MEK-ERK pathway was found hyper-phosphorylated in K562 RES cells even in the presence of dasatinib. Actually, ERK1/2 activity supported viability in K562 RES only in the absence of BCR-ABL1 activity. Finally, BCR-ABL1 and MEK inhibitor combination was sufficient to induce cell death even in non-proliferating resistant cells. Considering the conditions used to generate this dasatinib resistant cell line, such a resistance mechanism could be found in dasatinib treated patients. Consequently, it is valuable to know that inhibition of the MEK-ERK1/2 axis can overcome this resistance., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Although it has been well-demonstrated that bone marrow mesenchymal stromal cells (MSCs) from CML patients do not belong to the Ph1-positive clone, there is growing evidence that they could play a role in the leukemogenesis process or the protection of leukemic stem cells from the effects of tyrosine kinase inhibitors (TKIs). The aim of the present study was to identify genes differentially expressed in MSCs isolated from CML patients at diagnosis (CML-MSCs) as compared to MSCs from healthy controls. Using a custom gene-profiling assay, we identified six genes over-expressed in CML-MSCs (BMP1, FOXO3, MET, MITF, NANOG, PDPN), with the two highest levels being documented for PDPN (PODOPLANIN) and NANOG. To determine whether this aberrant signature persisted in patients in deep molecular response induced by TKIs, we analyzed MSCs derived from such patients (MR-MSCs). This analysis showed that, despite the deep molecular responses, BMP1, MET, MITF, NANOG, and PDPN mRNA were upregulated in MR-MSCs. Moreover, BMP1, MITF, and NANOG mRNA expressions in MR-MSCs were found to be intermediate between control MSCs and CML-MSCs. These results suggest that CML-MSCs exhibit an abnormal gene expression pattern which might have been established during the leukemogenic process and persist in patients in deep molecular response., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objective: The development of tyrosine kinase inhibitors (TKIs) has significantly improved the treatment of chronic myeloid leukemia (CML). However, approximately one third of patients are resistant to TKI and/or progress to advanced disease stages. TKI therapy failure has a well-known association with ABL1 kinase domain (KD) mutations, but only around half of TKI non-responders have detectable ABL1 KD mutations., Method: We attempt to identify genetic markers associated with TKI therapy failure in 13 patients (5 resistant, 8 progressed) without ABL1 KD mutations using whole-exome sequencing., Results: In 6 patients, we detected mutations in 6 genes commonly mutated in other myeloid neoplasms: ABL1, ASXL1, DNMT3A, IDH1, SETBP1, and TP63. We then used targeted deep sequencing to validate our finding in an independent cohort consisting of 100 CML patients with varying drug responses (74 responsive, 18 resistant, and 8 progressed patients). Mutations in genes associated with epigenetic regulations such as DNMT3A and ASXL1 seem to play an important role in the pathogenesis of CML progression and TKI-resistance independent of ABL1 KD mutations., Conclusion: This study suggests the involvement of other somatic mutations in the development of TKI resistant progression to advanced disease stages in CML, particularly in patients lacking ABL1 KD mutations., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Chronic myeloid leukemia (CML) patients who do not achieve landmark responses following treatment with imatinib mesylate (IM) are considered IM-resistant. Although IM-resistance can be due to BCR-ABL kinase domain (KD) mutations, many IM-resistant patients do not have detectable BCR-ABL KD mutations. MicroRNAs (miRNAs) are short non-coding RNAs that control gene expression. To investigate the role of miRNAs in IM-resistance, we recruited 8 chronic phase CML patients with IM-resistance who tested negative for BCR-ABL KD mutations and 2 healthy normal controls. Using miRNA sequencing, we identified 54 differentially expressed miRNAs; 43 of them downregulated. The 3 most differentially downregulated miRNAs were miR-146a-5p, miR-99b-5p and miR-151a-5p. Using real-time quantitative reverse transcriptase-polymerase chain reaction, the expression patterns of the 3 miRNAs were validated on the same cohort of 8 patients in addition to 3 other IM-resistant CML patients. In-silico analysis showed that the predicted gene targets are ATRIP, ATR, WDR48, RAD51C and FANCA genes which are involved in the Fanconi Anemia/BRCA pathway. This pathway regulates DNA damage response (DDR) and influences disease response to chemotherapy. Thus it is conceivable that DDR constitutes a key component in IM-resistance. Further research is needed to elucidate miRNA modulation of the predicted gene targets., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Introduction: Extensive studies on SHP-1 protein and SHP-1 mRNA revealed that the diminishment or abolishment of the expression of SHP-1 in leukemias/lymphomas was due to aberrant promoter methylation. Thus far, the mechanism of epigenetic silencing of the SHP-1 tyrosine phosphatase gene that occurs in chronic myelogenous leukemia cells remains poorly understood., Methods: The expressions of the target molecules were determined by quantitative real time PCR and western blot, respectively. Bisulfite sequencing PCR was used to detect methylation status of DNA CpG. The lentiviral vectors were applied to modify gene expression., Results: In the present study, we found that the promoter 2 of SHP-1 gene is located between positions from -577bp to +300bp, and 22 CpG sites contained in positions -353bp∼+182bp are aberrantly methylated in K562 cells. In vitro, we demonstrated that DNMT1 silencing induced demethylation of the 22 CpG sites located in the SHP-1 promoter and re-expression of SHP-1 gene in K562 cells. Moreover, we proved that the expression levels of DNMT1 and SHP-1 mRNA and protein were negatively correlated in K562 cells and BM aspirates mononuclear cells from CML patients., Conclusion: Collectively, these results indicate that DNMT1 mediates aberrant methylation and silencing of SHP-1 gene in chronic myelogenous leukemia cells, and provide a novel therapeutic target for CML., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Purpose: In patients with chronic myelogenous leukemia (CML), point mutations in the BCR-ABL1 kinase domain are the most common cause of treatment failure with a tyrosine kinase inhibitor (TKI). It is not clear whether the splice variant BCR-ABL1(35INS) is also associated with treatment failure., Patients and Methods: We reviewed all CML patients who had BCR-ABL1 kinase mutation analysis performed between August 1, 2007, and January 15, 2014. Patients who had BCR-ABL1(35INS) detected had their medical records reviewed to determine response to TKI therapy., Results: Two hundred and eighty four patients had kinase mutation testing performed; of these, 64 patients (23%) had BCR-ABL1(35INS) detected. Forty-five patients were in chronic phase (70%), 10 were in accelerated phase (16%), 6 were in blastic phase (9%), and 3 were in other settings (5%). Of the 34 chronic phase patients who began therapy with imatinib, 23 patients (68%) failed therapy: 8 patients (24%) had primary refractory disease, 11 patients (32%) progressed, and 4 patients (12%) had disease progression after dose interruption. In contrast to the patients with disease progression or lack of response, none of 23 patients who were responding to imatinib had BCR-ABL1(35INS) detected. DNA sequencing of commonly mutated spliceosomal genes SF3B1, U2AF1, SRSF2, ZRSR2, SFA31, PRPF408, U2A565, and SF1 did not reveal mutations in seven BCR-ABL1(35INS) -positive patients tested., Conclusions: The splice variant BCR-ABL1(35INS) is frequently found in patients who are resistant to imatinib. Mutations in the commonly mutated spliceosomal proteins do not contribute to this association., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Chronic myeloid leukemia (CML) has chronic and acute phases. In chronic phase myeloid differentiation is preserved whereas in acute phase myeloid differentiation is blocked. Acute phase CML resembles acute myeloid leukemia (AML). Chronic phase CML is caused by BCR-ABL1. What additional mutation(s) cause transition to acute phase is unknown and may differ in different persons with CML. BCL11A encodes a transcription factor and is aberrantly-expressed in several haematological and solid neoplasms. We analyzed BCL11A mRNA levels in subjects with chronic and acute phase CML. BCL11A transcript levels were increased in subjects with CML in acute phase compared with those in normals and in subjects in chronic phase including some subjects studied in both phases. BCL11A mRNA levels were correlated with percent bone marrow blasts and significantly higher in lymphoid versus myeloid blast crisis. Differentiation of K562 with butyric acid, a CML cell line, decreased BCL11A mRNA levels. Cytology and flow cytometry analyses showed that ectopic expression of BCL11A in K562 cells blocked differentiation. These data suggest BCL11A may operate in transformation of CML from chronic to acute phase in some persons., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Niemann-Pick disease type C1 (NPC1) is involved in cholesterol trafficking and may normally function as a transmembrane efflux pump. Previous studies showed that its dysfunction can lead to cholesterol and daunorubicin accumulation in the cytoplasmic endosomal/lysosomal system, lead to Niemann-Pick disease and resistance to anticancer drugs. In the present study, NPC1 was shown by microarray analysis to be more highly expressed in the Ph+ acute lymphoblastic leukemia cell line SUP-B15/RI, an imatinib-resistant variant of SUP-B15/S cells without bcr-abl gene mutation established in our lab. Further investigation revealed a defect in the functional capacity of the NPC1 protein demonstrated by filipin staining accompanied by a lower intracellular imatinib mesylate(IM) concentration by high-performance liquid chromatography in SUP-B15/RI compared with SUP-B15/S cells. Furthermore, U18666A, an inhibitor of NPC1 function, was used to block cholesterol trafficking to imitate the NPC1 defect in SUP-B15/S cells, leading to higher NPC1 expression, stronger filipin fluorescence, lower intracellular IM concentrations and greater resistance against IM. Samples from non-mutated relapsed Ph+ ALL patients also showed higher NPC1 expression compared with IM-sensitive patients. Our experiment may reveal a new mechanism of IM resistance in Ph+ ALL., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

To explore the factors for achieving early molecular responses (EMR; BCR-ABL1 ≤10% at 3 months, ≤1% at 6 months) by imatinib (IM), baseline characteristics including individual BCR-ABL1 transcript level, dose intensity, and IM trough level on day 29 were analyzed in 286 chronic phase chronic myeloid leukemia patients. Distinct predictive factors for achieving EMR at 3 months and 6 months were noted. Blast count at diagnosis and IM trough level on day 29 were significantly associated with an achievement of 3-month EMR. Early decline of BCR-ABL1 transcript, low Sokal risk, and mean daily dose (≥350mg/day) by 6 months were associated with an achievement of 6-month EMR. Understanding the predictive factors for EMR may provide additional information to guide clinical decisions on the changing therapies at each landmark., (Copyright © 2015. Published by Elsevier Ltd.)

The BCR-ABL transcript level (≤ 10%) at 3 months after tyrosine kinase inhibitors can predict long term outcome in the patients with chronic myeloid leukemia in chronic phase (CML-CP). However, the significance of transcript level was still not determined in different risk groups of patients. A total of 299 patients with CML-CP were enrolled and stratified according to prior interferon-α (IFN) treatment, age, and interval time between diagnosis and imatinib treatment to investigate the prediction value of BCR-ABL transcript level for overall survival (OS), event-free survival (EFS), progression-free survival (PFS). Univariate and multivariate analysis proved that BCR-ABL transcript level at 3 months were associated with the treatment outcome. However, in the patients with prior IFN treatment, younger age, and longer interval between diagnosis and IM treatment, the predictive value of transcript value remain obscure in terms of EFS, PFS and OS, respectively, as well as cumulative incidence of PCyR, CCR, MMR and CMR. In conclusion, the transcript level of BCR-ABL at 3 months could serve as a predictive parameter, but should be used with caution., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

CIAPIN1 (cytokine-induced antiapoptotic inhibitor 1) was recently identified as an essential downstream effector of the Ras signaling pathway. However, its potential role in regulating myeloid differentiation remains unclear. In this study, we found depletion of CIAPIN1 by shRNAs led to granulocytic differentiation of K562 cells. Meanwhile, the decrease of NHE1 and up-regulation of phosphorylated ERK1/2 were observed after CIAPIN1 depletion. Interestingly, targeted inhibition of NHE1 further promoted the differentiation of K562 cells with CIAPIN1 silencing. Accordingly, ectopic expression of NHE1 reversed this phenotype. Furthermore, ERK1/2 inhibition with the chemical inhibitor, PD98059, abolished CIAPIN1 silencing-induced differentiation of K562 cells after NHE1 inhibition. Thus, our results revealed important mechanism that CIAPIN1 targeted NHE1 to mediate differentiation of K562 cells via ERK1/2 pathway. Our findings implied CIAPIN1 and NHE1 could be new targets in developing therapeutic strategies against leukemia., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Human leukemia cell lines are of great value in leukemia research. In this study, we established and described the biological characteristics of a rare atypical chronic myeloid (aCML) leukemia cell line (NT-1). Mononuclear cells were isolated from the bone marrow of a patient with atypical chronic myeloid leukemia (Ph(-)/bcr(-)/abl(-)), and were passaged by liquid culture. Cells were maintained without any cytokines for over 1 year, and named NT-1. This cell line was extensively characterized using morphological assays, flow cytometry, cytogenetic analysis, clonogenic culture, quantitative fluorescent PCR, short tandem repeating sequence PCR (STR-PCR) and array-CGH. Its tumorigenic capacity was also examined in nude mice. The NT-1 cell line had morphological features of chronic myeloid leukemia and major myeloid markers (CD13, CD33, CD11b). Additionally, NT-1 expressed progenitor cells and natural killer cell-related antigens such as CD34, CD117, CD56. Cytogenetic analysis initially demonstrated two abnormalities: 47, xx, +8 and 47, xx, +8 accompanied by t(5;12)(q31;p13) translocation. The one-year passage process did not alter the karyotype. NT-1 cells maintained the same morphology, immunophenotyping and cytogenetic features as primary leukemia cells, which was strongly supported by STR-PCR results. Neither Epstein-Barr virus nor mycoplasma was detected in the NT-1 line. In addition, NT-1 cells showed high tumorigenic capacity in nude mice. NT-1 is a new atypical chronic myeloid leukemia cell line with the +8 and t(5,12) translocation, and exhibits high tumorigenicity in nude mice. This new cell line provides a useful tool for the study of leukemogenesis., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Resistance to chemotherapy is one of the most relevant aspects of treatment failure in cancer. Cell lines are used as models to study resistance. We analyzed the transcriptional profile of two multidrug resistant (MDR) cell lines (Lucena 1 and FEPS) derived from the same drug-sensitive cell K562. Microarray data identified 130 differentially expressed genes (DEG) between K562 vs. Lucena 1, 1932 between K562 vs. FEPS, and 1211 between Lucena 1 versus FEPS. The NOTCH pathway was affected in FEPS with overexpression of NOTCH2 and HEY1. The highly overexpressed gene in MDR cell lines was ABCB1, and both presented the ABCB1 promoter unmethylated., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Discovery of imatinib mesylate (IM) as the targeted BCR-ABL protein tyrosine kinase inhibitor (TKI) has resulted in its use as the frontline therapy for chronic myeloid leukemia (CML) across the world. Although high response rates are observed in CML patients who receive IM treatment, a significant number of patients develop resistance to IM. Resistance to IM in patients has been associated with a heterogeneous array of mechanisms of which point mutations within the ABL tyrosine kinase domain (TKD) are the frequently documented. The types and frequencies of mutations reported in different population studies have shown wide variability. We screened 125 Malaysian CML patients on IM therapy who showed either TKI refractory or resistance to IM to investigate the frequency and pattern of BCR-ABL kinase domain mutations among Malaysian CML patients undergoing IM therapy and to determine the clinical significance. Mutational screening using denaturing high performance liquid chromatography (dHPLC) followed by DNA sequencing was performed on 125 IM resistant Malaysian CML patients. Mutations were detected in 28 patients (22.4%). Fifteen different types of mutations (T315I, E255K, G250E, M351T, F359C, G251E, Y253H, V289F, E355G, N368S, L387M, H369R, A397P, E355A, D276G), including 2 novel mutations were identified, with T315I as the predominant type of mutation. The data generated from clinical and molecular parameters studied were correlated with the survival of CML patients. Patients with Y253H, M351T and E355G TKD mutations showed poorer prognosis compared to those without mutation. Interestingly, when the prognostic impact of the observed mutations was compared inter-individually, E355G and Y253H mutations were associated with more adverse prognosis and shorter survival (P=0.025 and 0.005 respectively) than T315I mutation. Results suggest that apart from those mutations occurring in the three crucial regions (catalytic domain, P-loop and activation-loop), other rare mutations also may have high impact in the development of resistance and adverse prognosis. Presence of mutations in different regions of BCR-ABL TKD leads to different levels of resistance and early detection of emerging mutant clones may help in decision making for alternative treatment. Serial monitoring of BCR-ABL1 transcripts in CML patients allows appropriate selection of CML patients for BCR-ABL1 KD mutation analysis associated with acquired TKI resistance. Identification of these KD mutations is essential in order to direct alternative treatments in such CML patients., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

We introduced SNX2-ABL1, a novel ABL1-related chimeric transcript lacks SH3 and SH2 domains, into murine Ba/F3 cells and compared their function with that of BCR-ABL1. After the expression of SNX2-ABL1 proteins, Ba/F3 cells acquired an ability to proliferate in an IL-3-independent manner. Upon treatment with both imatinib and dasatinib, BCR-ABL1-expressing Ba/F3 cells underwent rapid apoptosis, whereas SNX2-ABL1-expressing Ba/F3 cells showed poorer sensitivity toward these TKIs and could proliferate in the presence of a low dose of dasatinib. Therefore, other TKIs with a more selective effect against this chimeric kinase should be used for the treatment of patients with SNX2-ABL1+ ALL., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Sixty patients with early chronic phase CML (ECPCML) received Nilotinib on a phase II study which included a comparison of the Xpert BCR-ABL Monitor™ PCR system with standardized (IS) BCR-ABL1 real-time quantitative PCR (RQ-PCR). 88% patients achieved MMR with 45% achieving MR4.5. At 3 months BCR-ABL1/ABL1 IS >1% and <10% was associated with a lower likelihood of subsequent MR4.5 compared to patients with lower levels (p = 0.018). No significant difference was observed between methodologies in identifying MMR. Nilotinib induces high molecular response rates in ECPCML and the Xpert BCR-ABL Monitor™ system merits further investigation in this setting., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Flowcytometry analysis was carried out to evaluate the expression of the p-Stat3 in 50 CML patients and 20 age-matched healthy controls. p-Stat3 expression was increased in advanced stages of CML. Imatinib treatment was found to suppress the expression of p-Stat3 in bone marrow cells. The level of p-Stat3 was found to be higher in resistant cases than in responsive cases, which suggest the beneficial use of p-Stat3 as an indicator to follow the clinical course and the treatment response., (Copyright © 2013 Elsevier Ltd. All rights reserved.)