Lukáš Semerád

Mechanism of impaired glucose metabolism during nilotinib therapy in patients with chronic myelogenous leukemia

Hyperglycemia represents frequent adverse event reported in chronic myelogenous leukemia (CML) patients treated with nilotinib. In order to determine the major mechanism of glucose metabolism impairment, we performed a metabolic analysis using an oral glucose tolerance test as well as assessment of incretins and adipokines at baseline and after 3 months of nilotinib treatment in patients with CML. We proved that rapid insulin resistance, compensatory hyperinsulinaemia, and hypoadiponectinaemia develop after initiation of nilotinib therapy, which clarifies not only the mechanism of impaired glucose metabolism, but also explains the fast development of dyslipidaemia and peripheral artery occlusion in nilotinib-treated CML patients.

Quantitative assessment of the CD26+ leukemic stem cell compartment in chronic myeloid leukemia: patient-subgroups, prognostic impact, and technical aspects

Little is known about the function and phenotype of leukemic stem cells (LSCs) in chronic myeloid leukemia (CML) or about specific markers that discriminate LSCs from normal hematopoietic stem cells (HSCs). CD26 has recently been described as a specific marker of CML LSCs. In the current study, we investigated this marker in a cohort of 31 unselected CML patients. BCR/ABL1 positivity was analyzed in highly enriched stem cell fractions using fluorescence in situ hybridization (FISH) and reverse transcription PCR (RT-PCR). The proportion of CD26+ LSCs and CD26− HSCs varied considerably among the patients analyzed, and the percentage of CD26+ cells correlated with leukocyte count. The CD26 expression robustly discriminated LSCs from HSCs. This required a strict gating of the stem cell compartment. Thus, in patients with very low LSC or HSC numbers, only the highly sensitive RT-PCR method discriminated between clonal and non-clonal cells, while a robust FISH analysis required larger numbers of cells in both compartments. Finally, our data show that the numbers of CD26+ CML LSCs correlate with responses to treatment with BCR-ABL1 inhibitors.

Chromothripsis in acute myeloid leukemia: biological features and impact on survival

Chromothripsis is a one-step genome-shattering catastrophe resulting from disruption of one or few chromosomes in multiple fragments and consequent random rejoining and repair. This study define incidence of chromothripsis in 395 newly-diagnosed adult acute myeloid leukemia (AML) patients from three institutions, its impact on survival and its genomic background. SNP 6.0 or CytoscanHD Array (Affymetrix®) were performed on all samples. We detected chromothripsis with a custom algorithm in 26/395 patients. Patients harboring chromothripsis had higher age (p=.002), ELN high risk (HR) (p<.001), lower white blood cell (WBC) count (p=.040), TP53 loss and/or mutations (p<.001) while FLT3 (p=.025) and NPM1 (p=.032) mutations were mutually exclusive with chromothripsis. Chromothripsis-positive patients showed a worse overall survival (OS) (p<.001) compared with HR patients (p=.011) and a poor prognosis in a COX-HR optimal regression model. Chromothripsis presented the hallmarks of chromosome instability [i.e. TP53 alteration, 5q deletion, higher mean of copy number alteration (CNA), complex karyotype, alterations in DNA repair and cell cycle] and focal deletions on chromosomes 4, 7, 12, 16, 17. CBA. FISH showed that chromothripsis is associated with marker, derivative and ring chromosomes. In conclusion, chromothripsis frequently occurs in AML (6.6%) and influences patient prognosis and disease biology.

Novel complex mutation in NPM1 gene in patient with acute myeloid leukemia

Somatic heterozygous mutations of the nucleophosmin gene (NPM1) are the most frequent mutations in acute myeloid leukemia (AML) patients. Mutations occur in approximately one-third of all adult patients with AML and in one half of cytogenetically normal AML patients (CN-AML). Mutations are mostly insertions that cluster within exon 11 – at the level of transcript (Ensembl transcript ref ENST00000296930, 1758 base pairs [bp]) it means within exon 12 – at the level of genomic DNA (Ensembl gene ref ENSG00000181163, NCBI Gene ref 4869 related to the Ensembl transcript ref ENST00000517671, 1338 bp). Frame shift mutations of the NPM1 gene cause the elongation of nucleophosmin phosphoprotein and its aberrant cytoplasmic expression.

Prospective analysis of low-level BCR - ABL1 T315I mutation in CD34 cells of patients with de novo chronic myeloid leukemia

Th e detection of BCR – ABL1 kinase domain (KD) mutations is frequently associated with resistance to tyrosine kinase inhibitors (TKIs), which results in an impaired prognosis for patients with chronic myeloid leukemia (CML) [1]. Early detection of these mutations can potentially lead to early therapeutic intervention and optimization of an ongoing treatment strategy. Considering the hematopoiesis hierar- chy, it is expected that BCR – ABL1 mutation clones expand directly from hematopoietic stem cells or early progenitor cells [2]. It has already been reported that BCR – ABL1 KD mutations were detected in these cells before they occurred in bone marrow (BM) or peripheral blood (PB) [3]. Particu- lar focus should be given to the T315I mutation, which is resistant to all approved TKIs (imatinib, nilotinib and dasa- tinib) [4,5], meaning that early detection of this key BCR – ABL1 KD mutation in “ source ” cells could have potential clinical benefits.

New Drugs in the Treatment of Acute Myeloid Leukemia in the Elderly

BACKGROUND At the time of diagnosis, most patients with acute myeloid leukemia are older than 65 years of age. Treatment of this group of patients is challenging because they become less tolerant to aggressive chemotherapy with increasing age. Less than one-third of elderly patients are considered eligible for intensive treatment; nevertheless, the survival analysis for this population remains poor. Due to numerous comorbidities and an overall deteriorating condition, most elderly patients with acute myeloid leukemia receive only palliative or best supportive care, which are associated with a high mortality rate. New therapeutic approaches are expected to improve the overall survival and quality of life of this group of patients. These promising treatments include cell kinase inhibitors, cytotoxic agents, monoclonal antibodies, and epigenetic therapy including hypomethylating agents and inhibitors of isocitrate dehydrogenase and histone deacetylase. In monotherapy, these new drugs show lower levels of toxicity than those commonly used in chemotherapy; however, they do not lead to a better long-lasting treatment response. To enhance therapeutic efficacy, combinations of the above-mentioned treatments are often used, and, during clinical trials, combinations with standard cytostatics are also common. The promising results of these studies show that even low-toxicity therapies can lead to a better overall treatment response and to longer overall survival. AIM This article provides a brief overview of new drugs that are evaluated for their mechanism of effect, efficacy and toxicity in therapy of patients suffering from acute myeloid leukemia.Key words: acute myeloid leukemia - elderly - FLT3 inhibitors - epigenetic therapy - monoclonal antibodies The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 4. 11. 2016Accepted: 13. 12. 2016.

Limited efficacy of HLA-haploidentical peripheral blood stem cell infusion in treatment of elderly patients with acute myelogenous leukaemia.

The study showed no benefit of adding HLA-haploidentical PBSC infusion to intensive chemotherapy over standard treatment in elderly AML patients.