Detection of BCR/ABL fusion product in normoblasts in a case of chronic myelogenous leukemia

Profiling of miRNAs and their interfering targets in peripheral blood mononuclear cells from patients with chronic myeloid leukaemia

Introduction

MicroRNAs may be implicated in the acquisition of drug resistance in chronic myeloid leukemia as they regulate the expression of not only BCR-ABL1 but also genes associated with the activation of drug transfer proteins or essential signaling pathways.

Methods

To understand the impact of specifically expressed miRNAs in chronic myeloid leukemia and their target genes, we collected peripheral blood mononuclear cells (PBMC) from patients diagnosed with chronic myeloid leukemia (CML) and healthy donors to determine whole miRNA expression by small RNA sequencing and screened out 31 differentially expressed microRNAs (DE-miRNAs) with high expression. With the utilization of miRNA set enrichment analysis tools, we present here a comprehensive analysis of the relevance of DE-miRNAs to disease and biological function. Furthermore, the literature-based miRNA-target gene database was used to analyze the overall target genes of the DE-miRNAs and to define their associated biological responses. We further integrated DE-miRNA target genes to identify CML miRNA targeted gene signature singscore (CMTGSS) and used gene-set enrichment analysis (GSEA) to analyze the correlation between CMTGSS and Hallmark gene-sets in PBMC samples from clinical CML patients. Finally, the association of CMTGSS stratification with multiple CML cell lineage gene sets was validated in PBMC samples from CML patients using GSEA.

Results

Although individual miRNAs have been reported to have varying degrees of impact on CML, overall, our results show that abnormally upregulated miRNAs are associated with apoptosis and aberrantly downregulated miRNAs are associated with cell cycle. The clinical database shows that our defined DE-miRNAs are associated with the prognosis of CML patients. CMTGSS-based stratification analysis presented a tendency for miRNAs to affect cell differentiation in the blood microenvironment.

Conclusion

Collectively, this study defined differentially expressed miRNAs by miRNA sequencing from clinical samples and comprehensively analyzed the biological functions of the differential miRNAs in association with the target genes. The analysis of the enrichment of specific myeloid differentiated cells and immune cells also suggests the magnitude and potential targets of differentially expressed miRNAs in the clinical setting. It helps us to make links between the different results obtained from the multi-faceted studies to provide more potential research directions.

Chronic myeloid leukemia with pure erythroid leukemia blast crisis

Chronic myeloid leukemia (CML), a myeloproliferative neoplasm defined by the presence of the BCR-ABL1 oncogene created by the reciprocal translocation t(9;22)(q34.1;q11.2), can often be controlled by medications that inhibit this constitutive tyrosine kinase. However, if these therapies fail, the disease may progress to a form resembling an acute leukemia. While most of these CML 'blast crises' are characterized by blasts with a myeloid (granulocytic) or lymphoid lineage, these blasts may rarely be predominantly erythroid. Cases of CML erythroid blast crises have been reported; however, secondary pure erythroid leukemia arising from a CML blast crisis has only been definitively reported once before. We report the second definitive case of pure erythroid leukemia with the t(9;22)(q34.1;q11.2) presenting as a CML blast crisis and characterize the morphologic, immunophenotypic, flow cytometric, cytogenetic, and molecular findings.

Erythroid blast crisis in chronic myelogenous leukemia: Case report and review of literature

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder where over a period of time 15–20% of patients show blastic transformation with majority transforming into acute myeloid leukemia, most of which are of granulocytic lineage. Erythroid blast phase of CML is relatively rare with the incidence ranging from 0–10%. Further the incidence of acute erythroid leukemia by itself is fairly low amongst all acute leukemias. We report a case of 41-year-old patient with CML who failed to achieve cytogenetic remission, transformed to acute erythroid leukemia and eventually succumbed to the disease over a short period of time. Related literature is also reviewed

Concurrent megakaryocytic and erythroid chronic myelogenous leukemia blast crisis

Chronic myelogenous leukemia with blast crisis is seen in 15% to 20% of patients with chronic myelogenous leukemia. Chronic myelogenous leukemia with either erythroid or megakaryocytic blast crisis is not uncommon in the clinical setting. The incidence ranges from 0% to 33% in accordance with literature reports. The diagnosis of erythroid or megakaryocytic blast phase is often challenging because the percentage of blasts in the blood or bone marrow required for diagnosis has not been firmly established. Also, some myeloblasts can have aberrant expression of either erythroid or megakaryocytic markers by flow cytometry during clonal evolution. Early recognition of this entity is crucial because either megakaryocytic or erythroid blast crisis predicts an aggressive clinical course. To our knowledge, the coexistence of megakaryocytic and erythroid blasts has not been reported. We report a unique case of chronic myelogenous leukemia with this rare bilineage blast crisis in the background of dysplasia and marked myelofibrosis. Related literature is also reviewed.