Chronic myeloid leukaemia with soft tissue mass formed by mature granulocytes.

Extramedullary lesions in patients with chronic myeloid leukaemia (CML) suggest progression to the blast phase because such lesions generally consist of immature granulocytes. We here report a case of an extramedullary mass formed by mature granulocytes during the chronic phase of CML. A 60-year-old woman who had discontinued treatment for CML with dasatinib of her own accord several years ago presented to our hospital with a complaint of right thigh pain. She had a mass on her right leg, which was located on her right thigh and was elastic, soft and fist-sized. Blood tests and the bone marrow findings were compatible with the chronic phase of CML, and a CT-guided needle biopsy showed an infiltrate containing numerous mature neutrophils and foam cells. The mass disappeared with dasatinib alone, without antibacterial agents or drainage.Although the detailed pathogenesis of mass formation with mature granulocytes in the chronic phase of CML has not been elucidated, the clinical course of the current case highlights the importance of prompt biopsy, pathological examination and the early initiation of appropriate treatment.

RAPSYN-mediated neddylation of BCR-ABL alternatively determines the fate of Philadelphia chromosome-positive leukemia.

Philadelphia chromosome-positive (Ph+) leukemia is a fatal hematological malignancy. Although standard treatments with tyrosine kinase inhibitors (TKIs) have achieved remarkable success in prolonging patient survival, intolerance, relapse, and TKI resistance remain serious issues for patients with Ph+ leukemia. Here, we report a new leukemogenic process in which RAPSYN and BCR-ABL co-occur in Ph+ leukemia, and RAPSYN mediates the neddylation of BCR-ABL. Consequently, neddylated BCR-ABL enhances the stability by competing its c-CBL-mediated degradation. Furthermore, SRC phosphorylates RAPSYN to activate its NEDD8 E3 ligase activity, promoting BCR-ABL stabilization and disease progression. Moreover, in contrast to in vivo ineffectiveness of PROTAC-based degraders, depletion of RAPSYN expression, or its ligase activity decreased BCR-ABL stability and, in turn, inhibited tumor formation and growth. Collectively, these findings represent an alternative to tyrosine kinase activity for the oncoprotein and leukemogenic cells and generate a rationale of targeting RAPSYN-mediated BCR-ABL neddylation for the treatment of Ph+ leukemia.

Chronic myeloid leukemia (CML for short) accounts for about 15% of all blood cancers diagnosed in adults in the United States. The condition is characterized by the overproduction of immature immune cells that interfere with proper blood function. It is linked to a gene recombination (a type of mutation) that leads to white blood cells producing an abnormal 'BCR-ABL' enzyme which is always switched on. In turn, this overactive protein causes the cells to live longer and divide uncontrollably. Some of the most effective drugs available to control the disease today work by blocking the activity of BCR-ABL. Yet certain patients can become resistant to these treatments over time, causing them to relapse. Other approaches are therefore needed to manage this disease; in particular, a promising avenue of research consists in exploring whether it is possible to reduce the amount of the enzyme present in diseased cells. As part of this effort, Zhao, Dai, Li, Zhang et al. focused on RAPSYN, a scaffolding protein previously unknown in CML cells. In other tissues, it has recently been shown to participate in neddylation ­ a process by which proteins receive certain chemical 'tags' that change the way they behave. The experiments revealed that, compared to healthy volunteers, RAPSYN was present at much higher levels in the white blood cells of CML patients. Experimentally lowering the amount of RAPSYN in CML cells led these to divide less quickly ­ both in a dish and when injected in mice, while also being linked to decreased levels of BCR-ABL. Additional biochemical experiments indicated that RAPSYN sticks with BCR-ABL to add chemical 'tags' that protect the abnormal protein against degradation, therefore increasing its overall levels. Finally, the team showed that SRC, an enzyme often dysregulated in emerging cancers, can activate RAPSYN's ability to conduct neddylation; such mechanism could promote BCR-ABL stabilization and, in turn, disease progression. Taken together, these experiments indicate a new way by which BCR-ABL levels are controlled. Future studies should investigate whether RAPSYN also stabilizes BCR-ABL in patients whose leukemias have become resistant to existing drugs. Eventually, RAPSYN may offer a new target for overcoming drug-resistance in CML patients.

Derivatives of D(-) glutamine-based MMP-2 inhibitors as an effective remedy for the management of chronic myeloid leukemia-Part-I: Synthesis, biological screening and in silico binding interaction analysis.

Chronic myeloid leukemia (CML) is a global issue and the available drugs such as tyrosine kinase inhibitors (TKIs) comprise various toxic effects as well as resistance and cross-resistance. Therefore, novel molecules targeting specific enzymes may unravel a new direction in antileukemic drug discovery. In this context, targeting gelatinases (MMP-2 and MMP-9) can be an alternative option for the development of novel molecules effective against CML. In this article, some D(-)glutamine derivatives were synthesized and evaluated through cell-based antileukemic assays and tested against gelatinases. The lead compounds, i.e., benzyl analogs exerted the most promising antileukemic potential showing nontoxicity in normal cell line including efficacious gelatinase inhibition. Both these lead molecules yielded effective apoptosis and displayed marked reductions in MMP-2 expression in the K562 cell line. Not only that, but both of them also revealed effective antiangiogenic efficacy. Importantly, the most potent MMP-2 inhibitor, i.e., benzyl derivative of p-tosyl D(-)glutamine disclosed stable binding interaction at the MMP-2 active site correlating with the highly effective MMP-2 inhibitory activity. Therefore, such D(-)glutamine derivatives might be explored further as promising MMP-2 inhibitors with efficacious antileukemic profiles for the treatment of CML in the future.

Nutrient-sensitizing drug repurposing screen identifies lomerizine as a mitochondrial metabolism inhibitor of chronic myeloid leukemia.

In chronic myeloid leukemia (CML), the persistence of leukemic stem cells (LSCs) after treatment with tyrosine kinase inhibitors (TKIs), such as imatinib, can lead to disease relapse. It is known that therapy-resistant LSCs rely on oxidative phosphorylation (OXPHOS) for their survival and that targeting mitochondrial respiration sensitizes CML LSCs to imatinib treatment. However, current OXPHOS inhibitors have demonstrated limited efficacy or have shown adverse effects in clinical trials, highlighting that identification of clinically safe oxidative pathway inhibitors is warranted. We performed a high-throughput drug repurposing screen designed to identify mitochondrial metabolism inhibitors in myeloid leukemia cells. This identified lomerizine, a US Food and Drug Administration (FDA)-approved voltage-gated Ca2+ channel blocker now used for the treatment of migraines, as one of the top hits. Transcriptome analysis revealed increased expression of voltage-gated CACNA1D and receptor-activated TRPC6 Ca2+ channels in CML LSCs (CD34+CD38-) compared with normal counterparts. This correlated with increased endoplasmic reticulum (ER) mass and increased ER and mitochondrial Ca2+ content in CML stem/progenitor cells. We demonstrate that lomerizine-mediated inhibition of Ca2+ uptake leads to ER and mitochondrial Ca2+ depletion, with similar effects seen after CACNA1D and TRPC6 knockdown. Through stable isotope-assisted metabolomics and functional assays, we observe that lomerizine treatment inhibits mitochondrial isocitrate dehydrogenase activity and mitochondrial oxidative metabolism and selectively sensitizes CML LSCs to imatinib treatment. In addition, combination treatment with imatinib and lomerizine reduced CML tumor burden, targeted CML LSCs, and extended survival in xenotransplantation model of human CML, suggesting this as a potential therapeutic strategy to prevent disease relapse in patients.

The FABD domain is critical for the oncogenicity of BCR/ABL in chronic myeloid leukaemia.

BACKGROUND: Abnormally expressed BCR/ABL protein serves as the basis for the development of chronic myeloid leukaemia (CML). The F-actin binding domain (FABD), which is a crucial region of the BCR/ABL fusion protein, is also located at the carboxyl end of the c-ABL protein and regulates the kinase activity of c-ABL. However, the precise function of this domain in BCR/ABL remains uncertain. METHODS: The FABD-deficient adenovirus vectors Ad-BCR/ABL△FABD, wild-type Ad-BCR/ABL and the control vector Adtrack were constructed, and 32D cells were infected with these adenoviruses separately. The effects of FABD deletion on the proliferation and apoptosis of 32D cells were evaluated by a CCK-8 assay, colony formation assay, flow cytometry and DAPI staining. The levels of phosphorylated BCR/ABL, p73, and their downstream signalling molecules were detected by western blot. The intracellular localization and interaction of BCR/ABL with the cytoskeleton-related protein F-actin were identified by immunofluorescence and co-IP. The effect of FABD deletion on BCR/ABL carcinogenesis in vivo was explored in CML-like mouse models. The degree of leukaemic cell infiltration was observed by Wright‒Giemsa staining and haematoxylin and eosin (HE) staining. RESULTS: We report that the loss of FABD weakened the proliferation-promoting ability of BCR/ABL, accompanied by the downregulation of BCR/ABL downstream signals. Moreover, the deletion of FABD resulted in a change in the localization of BCR/ABL from the cytoplasm to the nucleus, accompanied by an increase in cell apoptosis due to the upregulation of p73 and its downstream proapoptotic factors. Furthermore, we discovered that the absence of FABD alleviated leukaemic cell infiltration induced by BCR/ABL in mice. CONCLUSIONS: These findings reveal that the deletion of FABD diminished the carcinogenic potential of BCR/ABL both in vitro and in vivo. This study provides further insight into the function of the FABD domain in BCR/ABL.

TIF1ß activates leukemic transcriptional program in HSCs and promotes BCR::ABL1-induced myeloid leukemia.

TIF1ß/KAP1/TRIM28, a chromatin modulator, both represses and activates the transcription of genes in normal and malignant cells. Analyses of datasets on leukemia patients revealed that the expression level of TIF1ß was increased in patients with chronic myeloid leukemia at the blast crisis and acute myeloid leukemia. We generated a BCR::ABL1 conditional knock-in (KI) mouse model, which developed aggressive myeloid leukemia, and demonstrated that the deletion of the Tif1ß gene inhibited the progression of myeloid leukemia and showed longer survival than that in BCR::ABL1 KI mice, suggesting that Tif1ß drove the progression of BCR::ABL1-induced leukemia. In addition, the deletion of Tif1ß sensitized BCR::ABL1 KI leukemic cells to dasatinib. The deletion of Tif1ß decreased the expression levels of TIF1ß-target genes and chromatin accessibility peaks enriched with the Fosl1-binding motif in BCR::ABL1 KI stem cells. TIF1ß directly bound to the promoters of proliferation genes, such as FOSL1, in human BCR::ABL1 cells, in which TIF1ß and FOSL1 bound to adjacent regions of chromatin. Since the expression of Fosl1 was critical for the enhanced growth of BCR::ABL1 KI cells, Tif1ß and Fosl1 interacted to activate the leukemic transcriptional program in and cellular function of BCR::ABL1 KI stem cells and drove the progression of myeloid leukemia.

Platelet microparticles influence gene expression and modulate biological activities of chronic myeloid leukemia cells (K562).

BACKGROUND: The current understanding emphasizes the intricate interplay between the Leukemic cell and its environment. Platelet-derived microparticles play a crucial role in facilitating intercellular communication and contribute to the complex landscape of cancer pathology. This study aimed to investigate the influence of platelet-derived microparticles on cell proliferation, apoptosis, and the expression of key genes, including P53, P21, Cyclin D1, Bax, and Bcl-2, within the context of a chronic myeloid leukemia cell line (K562). METHODS AND RESULTS: Platelet-derived microparticles were obtained through centrifugation at various speeds, and their concentration was quantified using the BCA assay. To determine the size and immunophenotypic characteristics of the PMPs, both the DLS technique and flow cytometry were employed. Cell proliferation was assessed using the MTT assay and hemocytometer, and cell cycle analysis was conducted through DNA content evaluation. Real-time PCR was utilized for gene expression analysis of Bax, Bcl-2, Cyclin D1, P53, and P21. Flow cytometry was employed to examine cell apoptosis. The findings revealed that platelet-derived microparticles have the ability to decrease proliferation of the K562 cell line, while not exerting an impact on apoptosis and cell cycle progression. Analysis through real-time PCR indicated an upregulation in the gene expression of P53, P21, and Bcl-2, accompanied by a downregulation in Bax and Cyclin D1. CONCLUSION: This investigation sheds light on the intricate relationship between chronic myeloid leukemia and its microenvironment, particularly the involvement of platelet-derived microparticles. The study underscores the potential of platelet-derived microparticles to influence cell behavior and gene expression, providing a deeper understanding of their role in CML and its therapeutic implications.

Integrated functional genomic screening to bypass TKI resistance in chronic myeloid leukemia.

CML is readily treatable with tyrosine kinase inhibitors (TKIs); however, resistance occurs, with the disease curable in only ∼15%-20% of patients. Using integrated functional genomics, Adnan Awad et al.1 identify agents effective against CML stem cells and describe mechanisms underlying TKI resistance.

Combination of an aurora kinase inhibitor and the ABL tyrosine kinase inhibitor asciminib against ABL inhibitor-resistant CML cells.

The development of BCR::ABL1-targeting tyrosine kinase inhibitors (TKIs) has improved the prognosis of patients with chronic myeloid leukemia (CML). However, resistance to ABL TKIs can develop in CML patients due to BCR::ABL1 point mutations and CML leukemia stem cell (LSC). Aurora kinases are essential kinases for cell division and regulate mitosis, especially the process of chromosomal segregation. Aurora kinase members also promote cancer cell survival and proliferation. This study analyzed whether aurora kinases were regulated in the progression of CML. It also evaluated the efficacy of the ABL TKI asciminib and the aurora kinase inhibitor LY3295668. The expressions of AURKA and AURKB were higher in the CML cells compared with normal cells using a public database (GSE100026). Asciminib or LY3295668 alone inhibited CML cells after 72 h, and cellular cytotoxicity was increased. The combined use of Asciminib and LY3295668 increased superior efficacy compared with either drug alone. Colony formation was reduced by cotreatment with asciminib and LY3295668. In the cell-cycle analyses, LY3295668 induced G2/M arrest. Cell populations in the sub-G1 phase were observed when cotreating with asciminib and LY3295668. The combination treatment also changed the mitochondrial membrane potential. In addition, AURKA shRNA transfectant cells had increased asciminib sensitivity. Combining asciminib and aurora kinase inhibition enhanced the efficacy and is proposed as a new therapeutic option for patients with CML. These findings have clinical implications for a potential novel therapeutic strategy for CML patients.

Does presence of complex translocations involving BCR::ABL1 in chronic myeloid leukemia affect the response rate to tyrosine kinase inhibitors? A systematic review of the literature.

Philadelphia (Ph) chromosome (9;22)(q34;q11) comprises 90-95 % of chronic myeloid leukemia (CML), while 5-10 % of CML have translocations involving three or more chromosomes. The outcome of treating patients harbouring complex Ph-positive cytogenetics with tyrosine kinase inhibitors (TKI) is unclear. In the present systematic review, we aim to summarise the response of patients with complex Ph-positive cytogenetics to treatment with TKI therapy. We collated all available literature from databases such as PubMed, Google Scholar, Web of Science database, Cochrane library, Scopus and Embase (up until January 31st, 2024), which describe cases of patients with CML, harbouring complex Ph-positive variations (three and four-way translocations), and summarised their response to TKI therapy. The studies were screened for the following criteria: documented TKI intervention and outcome (whether CR was achieved). Studies that did not report the same, were excluded. Additionally, we report a case from our center of a 55-year-old patient with CML, positive for the Ph-chromosome, harbouring a three-way translocation involving chromosome 15 i.e. 46XX, t(9;15;22) (q34;p11;q11). Identification of BCR::ABL and involvement of chromosome 15 was carried out using conventional cytogenetics, fluorescence in situ hybridization (FISH), and quantitative PCR (qPCR). Based on the inclusion criteria, a total of 15 studies were included from which a total of 87 cases were covered. Overall, we identified 38 unique complex three- and four-way translocations across 87 Ph-positive cases and found that 85 patients with complex Ph-positive cytogenetics achieved complete remission upon treatment and did not appear to have a lesser response to TKI therapy.

Integrated drug profiling and CRISPR screening identify BCR::ABL1-independent vulnerabilities in chronic myeloid leukemia.

BCR::ABL1-independent pathways contribute to primary resistance to tyrosine kinase inhibitor (TKI) treatment in chronic myeloid leukemia (CML) and play a role in leukemic stem cell persistence. Here, we perform ex vivo drug screening of CML CD34+ leukemic stem/progenitor cells using 100 single drugs and TKI-drug combinations and identify sensitivities to Wee1, MDM2, and BCL2 inhibitors. These agents effectively inhibit primitive CD34+CD38- CML cells and demonstrate potent synergies when combined with TKIs. Flow-cytometry-based drug screening identifies mepacrine to induce differentiation of CD34+CD38- cells. We employ genome-wide CRISPR-Cas9 screening for six drugs, and mediator complex, apoptosis, and erythroid-lineage-related genes are identified as key resistance hits for TKIs, whereas the Wee1 inhibitor AZD1775 and mepacrine exhibit distinct resistance profiles. KCTD5, a consistent TKI-resistance-conferring gene, is found to mediate TKI-induced BCR::ABL1 ubiquitination. In summary, we delineate potential mechanisms for primary TKI resistance and non-BCR::ABL1-targeting drugs, offering insights for optimizing CML treatment.

Analysis of CSF3R mutations in atypical chronic myeloid leukemia and other myeloid malignancies.

We report a series of patients with CSF3R-mutant (CSF3Rmut) atypical chronic myeloid leukemia (aCML), chronic neutrophilic leukemia (CNL) or other hematologic malignancies. We included 25 patients: 5 aCML and 4 CNL CSF3Rmut patients; 1 aCML, 2 CNL, and 2 myelodysplastic/myeloproliferative neoplasm, not otherwise specified patients without CSF3R mutation; and 11 CSF3Rmut patients with other diseases [8 acute myeloid leukemia (AML), 1 chronic myelomonocytic leukemia (CMML), 1 myelodysplastic syndrome (MDS), and 1 acute lymphoblastic leukemia (ALL)]. Patients with aCML or CNL were tested by Sanger sequencing and pyrosequencing to identify CSF3R T618I. Twenty-two patients underwent gene panel analysis. CSF3R mutations, mostly T618I (8/9), were found at high frequencies in both aCML and CNL patients [5/6 aCML and 4/6 CNL]. Two aCML patients in early adulthood with CSF3R T618I and biallelic or homozygous CEBPA mutations without other mutations presented with increased blasts and exhibited remission for >6 years after transplantation. The other 7 CSF3Rmut aCML or CNL patients were elderly adults who all had ASXL1 mutations and frequently presented with SEBP1 and SRSF2 mutations. Five AML patients had CSF3R exon 14 or 15 point mutations, and 6 other patients (3 AML, 1 CMML, 1 MDS, and 1 ALL) had truncating mutations, demonstrating differences in leukocyte counts and mutation status. In conclusion, CSF3R mutations were found at a higher frequency in aCML patients than in previous studies, which might reflect ethnic differences. Additional studies are needed to confirm these findings and the relationship between CSF3R and CEBPA mutations.

Unveiling IL6R and MYC as Targeting Biomarkers in Imatinib-Resistant Chronic Myeloid Leukemia through Advanced Non-Invasive Apoptosis Detection Sensor Version 2 Detection.

The management of chronic myelogenous leukemia (CML) has seen significant progress with the introduction of tyrosine kinase inhibitors (TKIs), particularly Imatinib. However, a notable proportion of CML patients develop resistance to Imatinib, often due to the persistence of leukemia stem cells and resistance mechanisms independent of BCR::ABL1 This study investigates the roles of IL6R, IL7R, and MYC in Imatinib resistance by employing CRISPR/Cas9 for gene editing and the Non-Invasive Apoptosis Detection Sensor version 2 (NIADS v2) for apoptosis assessment. The results indicate that Imatinib-resistant K562 cells (K562-IR) predominantly express IL6R, IL7R, and MYC, with IL6R and MYC playing crucial roles in cell survival and sensitivity to Imatinib. Conversely, IL7R does not significantly impact cytotoxicity, either alone or in combination with Imatinib. Further genetic editing experiments confirm the protective functions of IL6R and MYC in K562-IR cells, suggesting their potential as therapeutic targets for overcoming Imatinib resistance in CML. This study contributes to understanding the mechanisms of Imatinib resistance in CML, proposing IL6R and MYC as pivotal targets for therapeutic strategies. Moreover, the utilization of NIADS v2 enhances our capability to analyze apoptosis and drug responses, contributing to a deeper understanding of CML pathogenesis and treatment options.

Ponatinib and STAT5 Inhibitor Pimozide Combined Synergistic Treatment Applications Potentially Overcome Drug Resistance via Regulating the Cytokine Expressional Network in Chronic Myeloid Leukemia Cells.

Chronic myeloid leukemia (CML) is a clonal myeloproliferative hematological disease characterized by the chimeric breakpoint-cluster region/Abelson kinase1 (BCR::ABL1) oncoprotein; playing a pivotal role in CML molecular pathology, diagnosis, treatment, and possible resistance arising from the success and tolerance of tyrosine kinase inhibitor (TKI)-based therapy. The transcription factor STAT5 constitutive signaling, which is influenced by the cytokine signaling network, triggers BCR::ABL1-based CML pathogenesis and is also relevant to acquired TKI resistance. The unsuccessful therapeutic approaches targeting BCR::ABL1, in particular third-line therapy with ponatinib, still need to be further developed with alternative combination strategies to overcome drug resistance. As treatment with the STAT5 inhibitor pimozide in combination with ponatinib resulted in an efficient and synergistic therapeutic approach in TKI-resistant CML cells, this study focused on identifying the underlying amplification of ponatinib response mechanisms by determining different cytokine expression profiles in parental and ponatinib-resistant CML cells, in vitro. The results showed that expression of interleukin (IL) 1B, IL9, and IL12A-B was increased by 2-fold, while IL18 was downregulated by 2-fold in the ponatinib-resistant cells compared to sensitive ones. Importantly, ponatinib treatment upregulated the expression of 21 of the 23 interferon and IL genes in the ponatinib-resistant cells, while treatment with pimozide or a combination dose resulted in a reduction in the expression of 19 different cytokine genes, such as for example, inflammatory cytokines, IL1A-B and IL6 or cytokine genes associated with supporting tumor progression, leukemia stem cell growth or poor survival, such as IL3, IL8, IL9, IL10, IL12, or IL15. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis results showed that the genes were mainly enriched in the regulation of receptor signaling through the Janus kinase/signal transducer and activator of transcription pathway, cytokine-cytokine receptor interaction, and hematopoietic cell lineage. Protein-protein interaction analysis showed that IL2, IL6, IL15, IFNG, and others appeared in the top lists of pathways, indicating their high centrality and importance in the network. Therefore, pimozide could be a promising agent to support TKI therapies in ponatinib resistance. This research would help to clarify the role of cytokines in ponatinib resistance and advance the development of new therapeutics to utilize the STAT5 inhibitor pimozide in combination with TKIs.

Hematological, clinical, cytogenetic and molecular profiles of confirmed chronic myeloid leukemia patients at presentation at a tertiary care teaching hospital in Addis Ababa, Ethiopia: a cross-sectional study.

BACKGROUND: In low-income countries there is insufficient evidence on hematological, clinical, cytogenetic and molecular profiles among new CML patients. Therefore, we performed this study among newly confirmed CML patients at Tikur Anbesa Specialized Hospital (TASH), Ethiopia. OBJECTIVE: To determine the hematological, clinical, cytogenetic and molecular profiles of confirmed CML patients at tertiary care teaching hospital in Addis Ababa, Ethiopia. METHODS: A facility-based cross-sectional study was conducted to evaluate hematological, clinical, cytogenetic and molecular profiles of confirmed CML patients at TASH from August 2021 to December 2022. A structured questionnaire was used to collect the patients' sociodemographic information, medical history and physical examination, and blood samples were also collected for hematological, cytogenetic and molecular tests. Descriptive statistics were used to analyze the sociodemographic, hematological, clinical, cytogenetic and molecular profiles of the study participants. RESULTS: A total of 251 confirmed new CML patients were recruited for the study. The majority of patients were male (151 [60.2%]; chronic (CP) CML, 213 [84.7%]; and had a median age of 36 years. The median (IQR) WBC, RBC, HGB and PLT counts were 217.7 (155.62-307.4) x103/µL, 3.2 (2.72-3.6) x106/µL, 9.3 (8.2-11) g/dl and 324 (211-499) x 103/µL, respectively. All patients had leukocytosis, and 92.8%, 95.6% and 99.2% of the patients developed anemia, hyperleukocytosis and neutrophilia, respectively. Fatigue, abdominal pain, splenomegaly and weight loss were the common signs and symptoms observed among CML patients. Approximately 86.1% of the study participants were Philadelphia chromosome positive (Ph+) according to fluorescence in situ hybridization (FISH). P210, the major breakpoint protein, transcript was detected by both qualitative polymerase chain reaction (PCR) and quantitative real time polymerase chain reaction (PCR). CONCLUSION: During presentation, most CML patients presented with hyperleukocytosis, neutrophilia and anemia at TASH, Addis Ababa. Fatigue, abdominal pain, splenomegaly and weight loss were the most common signs and symptoms observed in the CML patients. Most CML patients were diagnosed by FISH, and p120 was detected in all CML patients diagnosed by PCR. The majority of CML patients arrive at referral center with advanced signs and symptoms, so better to decentralize the service to peripheral health facilities.

High Level of CD8+PD-1+ Cells in Patients with Chronic Myeloid Leukemia Who Experienced Loss of MMR after Imatinib Discontinuation.

Treatment-free remission (TFR) is achieved in approximately half of chronic myeloid leukemia (CML) patients treated with tyrosine kinase inhibitors. The mechanisms responsible for TFR maintenance remain elusive. This study aimed to identify immune markers responsible for the control of residual CML cells early in the TFR (at 3 months), which may be the key to achieving long-term TFR and relapse-free survival (RFS) after discontinuation of imatinib. Our study included 63 CML patients after imatinib discontinuation, in whom comprehensive analysis of changes in the immune system was performed by flow cytometry, and changes in the BCR::ABL1 transcript levels were assessed by RQ-PCR and ddPCR. We demonstrated a significant increase in the percentage of CD8+PD-1+ cells in patients losing TFR. The level of CD8+PD-1+ cells is inversely related to the duration of treatment and incidence of deep molecular response (DMR) before discontinuation. Analysis of the ROC curve showed that the percentage of CD8+PD-1+ cells may be a significant factor in early molecular recurrence. Interestingly, at 3 months of TFR, patients with the e13a2 transcript had a significantly higher proportion of the PD-1-expressing immune cells compared to patients with the e14a2. Our results suggest the important involvement of CD8+PD-1+ cells in the success of TFR and may help in identifying a group of patients who could successfully discontinue imatinib.

CRKL but not CRKII contributes to hemin-induced erythroid differentiation of CML.

Destruction of erythropoiesis process leads to various diseases, including thrombocytopenia, anaemia, and leukaemia. miR-429-CT10 regulation of kinase-like (CRKL) axis involved in development, progression and metastasis of cancers. However, the exact role of miR-429-CRKL axis in leukaemic cell differentiation are still unknown. The current work aimed to uncover the effect of miR-429-CRKL axis on erythropoiesis. In the present study, CRKL upregulation was negatively correlated with miR-429 downregulation in both chronic myeloid leukaemia (CML) patient and CR patient samples. Moreover, CRKL expression level was significantly decreased while miR-429 expression level was increased during the erythroid differentiation of K562 cells following hemin treatment. Functional investigations revealed that overexpression and knockdown of CRKL was remarkably effective in suppressing and promoting hemin-induced erythroid differentiation of K562 cells, whereas, miR-429 exhibited opposite effects to CRKL. Mechanistically, miR-429 regulates erythroid differentiation of K562 cells by downregulating CRKL via selectively targeting CRKL-3'-untranslated region (UTR) through Raf/MEK/ERK pathway. Conversely, CRKII had no effect on erythroid differentiation of K562 cells. Taken together, our data demonstrated that CRKL (but not CRKII) and miR-429 contribute to development, progression and erythropoiesis of CML, miR-429-CRKL axis regulates erythropoiesis of K562 cells via Raf/MEK/ERK pathway, providing novel insights into effective diagnosis and therapy for CML patients.

Drug-induced chylothorax as a rare pleural complication in dasatinib therapy for chronic myeloid leukaemia.

Chylothorax is a lymphatic chylous pleural effusion typically associated with traumatic (iatrogenic, non-iatrogenic) and non-traumatic (infections, malignancy, lymphatic disorders) aetiologies. Drug-induced chylothorax is uncommon and mostly reported in association with BCR-ABL tyrosine kinase inhibitor therapy.