Accelerated-phase CML: de novo and transformed.

Despite the dramatic improvements in outcomes for the majority of chronic myeloid leukemia (CML) patients over the past 2 decades, a similar improvement has not been observed in the more advanced stages of the disease. Blast phase CML (BP-CML), although infrequent, remains poorly understood and inadequately treated. Consequently, the key initial goal of therapy in a newly diagnosed patient with chronic phase CML continues to be prevention of disease progression. Advances in genomic investigation in CML, specifically related to BP-CML, clearly demonstrate we have only scratched the surface in our understanding of the disease biology, a prerequisite to devising more targeted and effective therapeutic approaches to prevention and treatment. Importantly, the introduction of the concept of "CML-like" acute lymphoblastic leukemia (ALL) has the potential to simplify the differentiation between BCR::ABL1-positive ALL from de novo lymphoid BP-CML, optimizing monitoring and therapeutics. The development of novel treatment strategies such as the MATCHPOINT approach for BP-CML, utilizing combination chemotherapy with fludarabine, cytarabine, and idarubicin in addition to dose-modified ponatinib, may also be an important step in improving treatment outcomes. However, identifying patients who are high risk of transformation remains a challenge, and the recent 2022 updates to the international guidelines may add further confusion to this area. Further work is required to clarify the identification and treatment strategy for the patients who require a more aggressive approach than standard chronic phase CML management.

Hemophagocytic Lymphohistiocytosis Appearing During Blast Phase of Chronic Myeloid Leukemia.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening illness with rapid progression and high mortality and is associated with genetic defects or can be induced by malignancies or severe infections. Most of the hematological malignancy-related HLH reported was accompanied by lymphoid neoplasms. METHODS: Here, we present an unusual case of HLH with co-existing blast phase of chronic myeloid leukemia (CML-BP). RESULTS: A diagnosis of AML-M5 with most likely concomitant HLH was made based on the clinical features, morphology, flow cytometry immunophenotyping, and genetics. Moreover, clinical characteristics were more suggestive of myeloid blast phase CML than de novo AML with the positive p210 BCR-ABL1. However, disease-causing mutations of HLH were not available, the patient probably had secondary malignancy-associated HLH induced by an acute infection. CONCLUSIONS: The case focuses on the contribution of bone marrow morphological examination in getting the first diagnostic clue of CML-BP concomitant with HLH.

Extramedullary early T-cell lymphoblastic crisis in a young pregnant chronic myeloid leukemia patient: Diagnosis with fine-needle aspiration cytology and flow cytometry.

Chronic myeloid leukemia (CML) most commonly presents in chronic phase. Blast crisis in CML is usually of myeloid phenotype, whereas among lymphoid lineage, B-cell lymphoblastic crisis is common. T lymphoblastic crisis is rare with near early T-cell precursor (ETP) immunophenotype being exceedingly rare and very little is known about its characteristics, treatment, and prognosis. Blast crisis can occur in extramedullary sites with lymph node being the most common site. CML is also less investigated and studied in pregnancy as it is considered a disease of older adults. We report a rare case of CML presenting in extramedullary site (lymph node) as extramedullary T-cell lymphoblastic crisis of near ETP immunophenotype in a young pregnant female, which was diagnosed on fine-needle aspiration cytology in combination with flow cytometry.

SOCS-2 gene expression at diagnosis does not predict for outcome of chronic myeloid leukemia patients on imatinib treatment.

SOCS-2 gene expression at diagnosis has been suggested as a predictor of clinical outcome in chronic myeloid leukemia (CML). In this study SOCS-2 and GUS expression levels were determined by real-time PCR in pretherapeutic samples at diagnosis. First, three patient groups were compared after assessment at 48 months: optimal molecular responders (n = 35), patients with resistance to imatinib (n = 28), and blast crisis patients (n = 27). A significant difference in SOCS-2 gene expression at diagnosis was observed comparing blast crisis vs. resistant patients (p = 0.042) and optimal responders (p = 0.010). Second, a validation sample of consecutively randomized patients (n = 123) was investigated. No discriminative SOCS-2 gene expression cutoff could be derived to predict molecular or cytogenetic response, progression-free or overall survival. Although SOCS-2 gene was differentially expressed at the time of diagnosis in blast crisis patients when compared to other groups, a prognostic impact in consecutively randomized patients was not observed.

Blast and accelerated phase CML: room for improvement.

Tyrosine kinase inhibitors (TKIs) revolutionized the treatment of chronic myeloid leukemia (CML). With TKI therapy, the percentage of patients who progress to accelerated phase (AP) or blast phase (BP) CML has decreased from more than 20% to 1% to 1.5% per year. Although AP- and BP-CML occur in a minority of patients, outcomes in these patients are significantly worse compared with chronic phase CML, with decreased response rates and duration of response to TKI. Despite this, TKIs have improved outcomes in advanced phase CML, particularly in de novo AP patients, but are often inadequate for lasting remissions. The goal of initial therapy in advanced CML is a return to a chronic phase followed by consideration for bone marrow transplantation. The addition of induction chemotherapy with TKI is often necessary for achievement of a second chronic phase. Given the small population of patients with advanced CML, development of novel treatment strategies and investigational agents is challenging, although clinical trial participation is encouraged in AP and BP patients, whenever possible. We review the overall management approach to advanced CML, including TKI selection, combination therapy, consideration of transplant, and novel agents.

Distinguishing Isolated Lymphoid Extramedullary Blast Crisis and Secondary Non-Hodgkin Lymphoma in Chronic Myelogenous Leukemia: a Case Report and Review of the Literature.

Extramedullary blast crisis (EBC) is a special kind of blast crisis of chronic myelogenous leukemia (CML). It is more likely to be misdiagnosed as lymphoma when EBC cells are of lymphoid cell lineage and lymphadenopathy is the only symptom before the final diagnosis. In this study, we presented a patient with an unusual presentation of CML transformation as a rapid growth of generalized lymphadenopathy that appeared 5 months after the initial diagnosis of CML. The patient underwent the left supraclavicular lymph node biopsy and repeat bone marrow aspiration. The revealed CD3+, terminal deoxynucleotidyl transferase (TdT)+, CD5+, CD23+, myeloperoxidase (MPO)-, CD20-, cyclin D1-, CD10-, which was consistent with the diagnosis of T-cell lymphoblastic lymphoma (T-LBL). Fluorescence in situ hybridization (FISH) verified the BCR-ABL rearrangement, and T-cell EBC of CML was finally diagnosed. Our report suggested that FISH was necessary to distinguish isolated lymphoid extramedullary blast crisis from secondary NHL in CML.

RUNX1 mutations in blast-phase chronic myeloid leukemia associate with distinct phenotypes, transcriptional profiles, and drug responses.

Blast-phase chronic myeloid leukemia (BP-CML) is associated with additional chromosomal aberrations, RUNX1 mutations being one of the most common. Tyrosine kinase inhibitor therapy has only limited efficacy in BP-CML, and characterization of more defined molecular subtypes is warranted in order to design better treatment modalities for this poor prognosis patient group. Using whole-exome and RNA sequencing we demonstrate that PHF6 and BCORL1 mutations, IKZF1 deletions, and AID/RAG-mediated rearrangements are enriched in RUNX1mut BP-CML leading to typical mutational signature. On transcriptional level interferon and TNF signaling were deregulated in primary RUNX1mut CML cells and stem cell and B-lymphoid factors upregulated giving a rise to distinct phenotype. This was accompanied with the sensitivity of RUNX1mut blasts to CD19-CAR T cells in ex vivo assays. High-throughput drug sensitivity and resistance testing revealed leukemia cells from RUNX1mut patients to be highly responsive for mTOR-, BCL2-, and VEGFR inhibitors and glucocorticoids. These findings were further investigated and confirmed in CRISPR/Cas9-edited homozygous RUNX1-/- and heterozygous RUNX1-/mut BCR-ABL positive cell lines. Overall, our study provides insights into the pathogenic role of RUNX1 mutations and highlights personalized targeted therapy and CAR T-cell immunotherapy as potentially promising strategies for treating RUNX1mut BP-CML patients.

Sudden blast phase in pediatric chronic myeloid leukemia-chronic phase with abnormal lymphoid blasts detected by flow cytometry at diagnosis: Can it be considered a warning sign?

BACKGROUND: Inconclusive knowledge persists regarding the course of chronic myeloid leukemia-chronic phase (CML-CP) patients with detectable abnormal blasts by flow-cytometry at diagnosis. The 2016 WHO classification is not specific regarding sub-classification of CML with <10% abnormal B-lymphoid blasts (ABLB), and suggests these patients often show rapid progression. We report the clinical course of pediatric CML-CP patients who had detectable abnormal blasts by flow-cytometry at baseline. METHODS: Retrospective audit of all pediatric CML patients between January 2013 and December 2017 were included. Their clinical presentation, demographic profile, and treatment outcomes were extracted from electronic medical records. Some of these patients got flow-cytometry done by default, though it was not a routine part of diagnostic CML marrow studies. RESULTS: Amongst 65 pediatric CML patients, flow-cytometry at initial diagnosis was available in 15 (CP-12; AP-3). Of the 12 CML-CP patients, 10 (83%) had abnormal flow-cytometric findings-5 (50%) with mixed lineage blasts (4-B/Myeloid, 1-B/T/Myeloid), and myeloid lineage blasts in the remaining 5 (50%). At a median follow-up of 26 months (range: 9-34 months), 3/5 patients with ABLB at diagnosis progressed to frank blast crisis (2 B-cell; 1 Mixed lineage). None among the five patients with diagnostic myeloid-alone aberrant blasts progressed to blast crisis. Imatinib resistant mutation was also found in 3/5 (60%) CML-CP patients with these ABLB at baseline. CONCLUSIONS: Although a retrospective study with limited sample size, presence of ABLB detected on flow-cytometry in CML-CP patients, had a noticeable early conversion to CML-BC in our cohort. Incorporation of flow-cytometry in diagnostic work-up can provide useful insight regarding the behavior of pediatric CML-CP patients and guide therapy.

Chronic myelomonocytic leukemia - a review.

INTRODUCTION: Chronic myelomonocytic leukemia (CMML) is a clonal myeloid neoplasm, denoted by overlapping myelodysplastic and myeloproliferative features, with poor overall survival and high transformation rate to acute myeloid leukemia. AREAS COVERED: This review, following a thorough Medline search of pertinent published literature, discusses the diagnostic criteria, the pathogenesis, and the complex genetic landscape of the disease. Prognostication, response criteria, therapeutic management of patients, efficacy of established and novel treatment modalities are thoroughly reviewed. EXPERT OPINION: Cytogenetic abnormalities and mutations in genes involved in epigenetic and transcriptional regulation, and cell-signaling are abundant in CMML and implicated in its complex pathogenesis. As presence of these mutations carry a prognostic impact, they are increasingly incorporated in risk-stratification schemes. Novel response criteria have been proposed, considering the unique features of the disease. Although allogeneic hematopoietic stem cell transplantation remains the only treatment with curative intent, it is reserved for a minority of patients; therefore, there is an unmet need for optimizing treatment modalities, such as hypomethylating agents, and introducing novel agents, which could substantially improve survival and quality of life of CMML patients. Clinical trials dedicated specifically to CMML are needed to explore the efficacy and safety of novel treatment modalities.

Isolated blast crisis relapse in the central nervous system of a patient treating for a chronic myelogenous leukemia.

Chronic myeloid leukemia (CML) is a myeloproliferative disorder associated with the Philadelphia chromosome t (9;22) and the BCR-ABL fusion gene. The condition is relatively rare, accounting for 2.0% to 3.0% of childhood leukemia cases. CML has historically been a triphasic disease. Most patients are diagnosed in chronic phase. Without treatment, it inevitably progresses into a more aggressive accelerated phase and blast crisis. Some proportion of CML cases of blastic transformation develop an extramedullary disease that involves rarely central nervous system. This report describe an extremely rare case of 13-year-old girl with CML and extramedullary blast crisis in the central nervous system. Treatment options and monitoring of disease response are discussed.

Chronic myeloid leukemia presenting in lymphoblastic crisis, a differential diagnosis with Philadelphia-positive B-lymphoblastic leukemia.

Rare patients with chronic myeloid leukemia (CML) can present initially in lymphoblastic crisis (LBC) mimicking Ph + B-lymphoblastic leukemia (B-ALL). We retrospectively reviewed 275 adults who diagnosed initially as Ph + B-ALL and identified 28 patients with at least one of three features supporting the diagnosis of CML-LBC: 1) a large discrepancy between the blast count and Ph + clone; 2) Ph + clone persistent when B-ALL in remission; 3) BCR/ABL1 fusion detected in segmented cells. BCR-ABL1 fusions were p210 in 25 patients and p190 in 3 patients. In comparison to patients with Ph + B-ALL, patients with CML-LBC were older; had higher leukocyte and absolute neutrophil counts; higher immature myeloid cells in peripheral blood; lower blast counts; and inferior outcomes. In addition, we prospectively analyzed 26 patients with Ph + B-lymphoblastic leukemia and identified 8 patients with features more consistent with CML-LBC. These findings highlight the importance of distinguishing CML-LBC from de novo Ph + B-ALL.

Epidural myeloid sarcoma as the presenting symptom of chronic myeloid leukemia blast crisis.

Epidural myeloid sarcoma revealing chronic myeloid leukemia is scarce. Herein, we describe a patient that presented with back pain and bilateral sciatica secondary to root compression due to epidural deposition of leukemic cells. The magnetic resonance imaging showed epidural masses, causing a slight restriction of the spinal canal with bilateral L5 root compression. Laboratory examinations showed hyperleukocytosis (white blood cell count: 83 × 109/L, absolute neutrophil count: 60 × 109/L). The bone marrow cytology and immunophenotypic findings confirmed the diagnosis of myeloid leukemia. The diagnosis of spinal myeloid sarcoma revealing chronic myeloid leukemia during the blast phase was established. The patient underwent induction chemotherapy. Then, bone marrow cytology revealed less than 3% of blasts, which correspond to cytological remission. Three months later, MRI showed complete disappearance of the epidural masses. A literature review was conducted by searching PubMed using these terms: "Leukemia, Myeloid" AND "Spine" AND "Sarcoma, Myeloid". We emphasize clinical and radiological findings of spinal myeloid sarcoma. This diagnosis should be considered when the MRI reveals epidural mass lesion. The early management of this disease is necessary, and the treatment of myeloid sarcoma is not codified. Our case highlighted that chemotherapy treatment could be sufficient to lead to the disappearance of myeloid sarcoma and the remission of leukemia.

Clonal evolution of AML1-ETO coexisting with BCR-ABL and additional chromosome abnormalities in a blastic transformation of chronic myeloid leukemia.

Blast crisis develops in a minority of patients with chronic myeloid leukemia even in the era of tyrosine kinase inhibitor (TKI) therapy. Reports suggest that we know little about the mechanism of BCR-ABL and AML1-ETO co-expression in blast crisis of chronic myeloid leukemia, and that other chromosomal abnormalities also coexist. Here, we document an unusual and interesting case of a 51-year-old female diagnosed in the chronic phase of chronic myeloid leukemia. After undergoing TKI treatment for 3 months, her bone marrow aspirates in the chronic phase had transformed to blast crisis. Molecular genetic testing indicated she was positive for p210 form of BCR-ABL (copy number decreased from 108.91% to 56.96%) and AML1-ETO fusion (copy number, 5.65%) genes and had additional chromosomal abnormalities of t(8; 21)(q22; q22)/t(9; 22)(q34; q11), t(2; 5)(p24; q13) and an additional +8 chromosome.

Characterizing false-positive fluorescence in situ hybridization results by mate-pair sequencing in a patient with chronic myeloid leukemia and progression to myeloid blast crisis.

Traditional cytogenetic testing methodologies, including conventional chromosome analysis and fluorescence in situ hybridization (FISH), are invaluable for the detection or recurrent genetic abnormalities in various hematologic malignancies. However, technological advances, including a novel next-generation sequencing technique termed mate-pair sequencing (MPseq), continue to revolutionize the field of cytogenetics by enabling the characterization of structural variants at a significantly higher resolution compared to traditional methodologies. To illustrate the power of MPseq, we present a 27-year-old male diagnosed with chronic myeloid leukemia in myeloid blast crisis with multiple chromosomal abnormalities observed in all 20 metaphases from a peripheral blood specimen, including t(9;22)(q34;q11.2) and t(4;11)(q12;p15). Suspicious of a novel NUP98/PDGFRA fusion [t(4;11)(q12;p15)], break-apart FISH probe sets for the PDGFRA (4q12) and NUP98 (11p15.4) gene regions were performed and were both positive in approximately 86% of 200 interphase nuclei. However, subsequent MPseq testing revealed breakpoints located within the NUP98 gene and within an intergenic region (4q12) located between the CHIC2 and PDGFRA genes, indicating this 4;11 translocation does not result in the predicted NUP98/PDGFRA gene fusion as inferred from FISH and conventional chromosome results. This case demonstrates the clinical utility of MPseq, particularly for characterizing novel gene fusion events which may ultimately identify a false-positive FISH result.