Megakaryocytic blast crisis as first presentation of chronic myeloid leukemia

Comparative Gene Expression Analysis Reveals Similarities and Differences of Chronic Myeloid Leukemia Phases

Chronic myeloid leukemia (CML) is a slowly progressing blood cancer that primarily affects elderly people. Without successful treatment, CML progressively develops from the chronic phase through the accelerated phase to the blast crisis, and ultimately to death. Nowadays, the availability of targeted tyrosine kinase inhibitor (TKI) therapies has led to long-term disease control for the vast majority of patients. Nevertheless, there are still patients that do not respond well enough to TKI therapies and available targeted therapies are also less efficient for patients in accelerated phase or blast crises. Thus, a more detailed characterization of molecular alterations that distinguish the different CML phases is still very important. We performed an in-depth bioinformatics analysis of publicly available gene expression profiles of the three CML phases. Pairwise comparisons revealed many differentially expressed genes that formed a characteristic gene expression signature, which clearly distinguished the three CML phases. Signaling pathway expression patterns were very similar between the three phases but differed strongly in the number of affected genes, which increased with the phase. Still, significant alterations of MAPK, VEGF, PI3K-Akt, adherens junction and cytokine receptor interaction signaling distinguished specific phases. Our study also suggests that one can consider the phase-wise CML development as a three rather than a two-step process. This is in accordance with the phase-specific expression behavior of 24 potential major regulators that we predicted by a network-based approach. Several of these genes are known to be involved in the accumulation of additional mutations, alterations of immune responses, deregulation of signaling pathways or may have an impact on treatment response and survival. Importantly, some of these genes have already been reported in relation to CML (e.g., AURKB, AZU1, HLA-B, HLA-DMB, PF4) and others have been found to play important roles in different leukemias (e.g., CDCA3, RPL18A, PRG3, TLX3). In addition, increased expression of BCL2 in the accelerated and blast phase indicates that venetoclax could be a potential treatment option. Moreover, a characteristic signaling pathway signature with increased expression of cytokine and ECM receptor interaction pathway genes distinguished imatinib-resistant patients from each individual CML phase. Overall, our comparative analysis contributes to an in-depth molecular characterization of similarities and differences of the CML phases and provides hints for the identification of patients that may not profit from an imatinib therapy, which could support the development of additional treatment strategies.

Chronic myeloid leukemia blast crisis presented with AML of t(9;22) and t(3;14) mimicking acute lymphocytic leukemia

BACKGROUND

Clinically, 90%-95% of cases of CML have the characteristic t(9;22) (q34.1;q11.2) translocation that leads to the Philadelphia (Ph) chromosome. Rarely, patients with CML can present directly in a blast crisis (BC). While most blast crises are of myeloid origin, myeloid BC with ALL-like morphologic features and Ph-positive acute myeloid leukemia (AML) is rare, especially at the time of CML diagnosis.

CASE PRESENTATION

A 20-year-old man presented with Ph chromosome-positive AML mimicking acute lymphocytic leukemia (ALL). Bone marrow (BM) aspiration revealed AML with ALL-like morphologic features. The results of the immunophenotypic analysis suggested AML. Cytogenetic analysis of the BM cells revealed a 46,XY,t(3;14)(q21;q32),t(9;22)(q34;q11.2)[20] karyotype. Thus, we called the condition AML mimicking ALL. The patient was diagnosed with myeloid BC based on the combination of clinical, cytologic, and cytogenetic studies.

CONCLUSION

To date, no case reports of a patient diagnosed with CML BC presented with Ph chromosome-positive AML mimicking ALL have been reported. We present the case given its rarity, easy misdiagnosis, and poor prognosis. It is important to combine clinical, cytologic, and cytogenetic analyses in distinguishing CML BC from de novo AML with the t(9;22)，and further cases should be accumulated to explore how to improve the prognosis of the patients.

CML with Megakaryocytic Blast Crisis: Report of 3 Cases

Chronic myelogenous leukemia (CML) is a chronic myeloproliferative neoplasm consistently associated with the BCR-ABL1 fusion gene located in the Philadelphia chromosome. The Blast Phase is diagnosed when blasts are ≥20% of the peripheral blood white cell count or of bone marrow nucleated cells or when there is an extramedullary blast proliferation. Megakaryocytic blast crisis as the presenting manifestation of CML is extremely rare and only 7 reported cases were found in the literature. Out of 34 cases of CML-Blast Phase between April 2015 and June 2016, 3 cases showed megakaryocytic differentiation. 2 of these presented in Blast phase as the first manifestation of CML and the third case was a known case of CML-Chronic phase. Flow cytometric immunophenotyping was performed on peripheral blood/bone marrow using 6- color flow cytometer Navios. On CD45 vs SSC two distinct populations of blasts were seen in two cases and single population in the third case. All the 3 cases were positive for CD61, cCD41, cCD61 confirming the megakaryocytic lineage. The clinical features, morphologic and cytogenetic findings help in the identification and distinction of megakaryocytic blast phase of CML from Acute Megakayoblastic Leukemia. The diagnosis of such rare presentation of CML is essential for determining the choice of treatment. Therefore including a megakaryocytic marker in the primary flow cytometry panel is important so that these cases are not under-diagnosed as Acute myeloid leukemia because of expression of CD13 and CD33 only.

In vitro effects of imatinib on CD34+ cells of patients with chronic myeloid leukemia in the megakaryocytic crisis phase

Imatinib is a tailored drug for the treatment of chronic myeloid leukemia (CML), and has substantial activity and a favorable safety profile when used as a single agent in patients with CML in myeloid blast crisis. The megakaryocytic blast crisis in CML occurs rarely and carries a poor prognosis. The aim of the present study was to investigate the effects of imatinib on cluster of differentiation (CD)34⁺ cells from patients with CML in the megakaryocytic crisis phase. Bone marrow mononuclear cells (BMNCs) were isolated from patients with CML in the megakaryocytic crisis phase. CD34⁺ cells were selected from BMNCs by positive immunomagnetic column separation. Imatinib significantly induced G₁ arrest, reduced the phosphorylation of cyclin-dependent kinase 1 and retinoblastoma proteins and inhibited the proliferation of CD34⁺ cells from patients with CML in the megakaryocytic crisis phase. Annexin V/propidium iodide and caspase-3 activity showed that imatinib induced apoptosis. Western blot analysis and protein tyrosine kinase activity assays showed that imatinib inhibited BCR-ABL protein tyrosine kinase activity. The in vitro data thus markedly indicate a potential clinical application of imatinib for patients with CML in the megakaryocytic crisis phase.

De novo acute megakaryoblastic leukemia with p210 BCR/ABL and t(1;16) translocation but not t(9;22) Ph chromosome

Acute megakaryoblastic leukemia (AMKL) is a type of acute myeloid leukemia (AML), in which majority of the blasts are megakaryoblastic. De novo AMKL in adulthood is rare, and carries very poor prognosis. We here report a 45-year-old woman with de novo AMKL with BCR/ABL rearrangement and der(16)t(1;16)(q21;q23) translocation but negative for t(9;22) Ph chromosome. Upon induction chemotherapy consisting of homoharringtonine, cytarabine and daunorubicin, the patient achieved partial hematological remission. The patient was then switched to imatinib plus one cycle of CAG regimen (low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor), and achieved complete remission (CR). The disease recurred after 40 days and the patient eventually died of infection. To the best of our knowledge, this is the first report of de novo AMKL with p210 BCR/ABL and der(16)t(1;16)(q21;q23) translocation but not t(9;22) Ph chromosome.

[Stroke in cancer patients. A paraneoplastic neurological syndrome?]

The coincidence of stroke and cancer is frequently encountered. From recent epidemiological data, the stroke risk in cancer patients seems to be equally distributed as compared to the non-cancer population. However, there are several clinical conditions in cancer patients which increase the risk for stroke: Trousseau's syndrome, non-bacterial thrombotic endocarditis and disseminated intravascular coagulation. Also some tumour-specific conditions such as coagulopathies, changes of viscosity and cellular mechanisms such as leukocytosis or thrombocytopathies must be considered. In several types of tumour treatment, such as various anticancer drugs, an increased occurrence of stroke has been reported. Presently there is no indication that stroke and cancer are related to the immune-mediated "classic" paraneoplastic syndromes. However, there are several cancer-specific types and causes of stroke which need to be considered in each patient, as they can be of significance in the treatment.

Megakaryocytic blast crisis at presentation in a pediatric patient with chronic myeloid leukemia

Patients with chronic myeloid leukemia (CML) infrequently present in blast crisis (BC). While most BC are of myeloid origin, megakaryocytic BC is rare, especially at the time of CML diagnosis. We describe the first pediatric patient presenting with megakaryocytic leukemia and having BCR-ABL1 translocation as the single chromosomal abnormality. Clinical features were more suggestive of CML in megakaryocytic blast crisis than Philadelphia chromosome positive de novo AML. The patient was treated with AML-directed chemotherapy and imatinib mesylate followed by umbilical cord blood stem cell transplantation. The patient was in complete molecular response 16 months after stem cell transplantation.