Dana Dvořáková

Constant BCR-ABL transcript level ≥0.1% (IS) in patients with CML responding to imatinib with complete cytogenetic remission may indicate mutation analysis

OBJECTIVE Of 140 chronic myeloid leukemia patients responding to imatinib with complete cytogenetic remission, 32 exhibited a plateau of BCR-ABL values at >or=0.1% level in a minimum of three subsequent samples (minimal duration, 6 - 9 months). Median follow-up of unchanged BCR-ABL transcript level was 12 months (range, 6 - 64). We tested this group of patient for BCR-ABL mutations to reveal resistance development and to evaluate the risk of disease progression. MATERIALS AND METHODS Altogether, 134 samples of peripheral blood of these 32 patients were tested for mutation in BCR-ABL kinase domain. RESULTS Mutation was detected by direct sequencing in 9 of 32 patients (28%). Loss of complete cytogenetic remission or 1 log rise of BCR-ABL was observed in five of nine patients at a median of 5 months (range, 4-17) since first detection of mutation. One patient with no mutation relapsed 12 months after the start of the BCR-ABL plateau. In 5 of 32 patients without mutation (16%), BCR-ABL level significantly decreased after the first plateau to levels that stayed unchanged for a median of 11 months (range, 7-28). CONCLUSION We show here that the BCR-ABL constant levels >or=0.1% (BCR-ABL plateau) in imatinib-responding patients may indicate mutation analysis. This approach highly reduces the number of examinations for mutation in chronic myeloid leukemia responders and may present cost-effective alternative applicable in clinical practice.

Assessment of adenosine triphosphate-binding cassette subfamily B member 1 (ABCB1) mRNA expression in patients with de novo chronic myelogenous leukemia: the role of different cell types

In this study, we investigated differences in ABCB1 mRNA expression measured in peripheral blood (PB) leukocytes (LEU) as well as polymorphonuclear (PMNCs) and mononuclear cells (MNCs) of PB LEU obtained from healthy volunteers and patients with de novo CML. In addition, we analyzed the relationship between the percentage of individual cells that comprise the total LEU count and ABCB1 mRNA expression assessed from the total LEU. We have shown that ABCB1 mRNA transcript levels are significantly higher in PB MNCs than in PB PMNCs and are lower in patients with de novo CML compared to healthy individuals. Moreover, we have demonstrated the importance of the cell composition of analyzed samples in ABCB1 mRNA expression analysis.

Phenylketonuria mutations and their relation to RFLP haplotypes at the PAH locus in Czech PKU families

A detailed study of the mutant phenylalanine hydroxylase (PAH) gene from the eastern part of the Czech Republic (Moravia) is reported. A total of 190 mutant alleles from 95 phenylketonuria (PKU) families were analyzed for 21 prevalent Caucasian mutations and restriction fragment length polymorphism /variable number of tandem repeats (RFLP/VNTR) haplotypes. Eighty per cent of all mutant alleles were found to carry 11 mutations. The most common molecular defect was the mutation R408W (55.3%), with a very high degree of homozygosity (34.6%). Each of four other mutations (R158Q, R243X, G272X, IVS12nt1) accounted for more than 3% of PKU alleles. Rarely present were mutations IVS10nt546 (2.6%), R252W (2.6%), L48S (2.1%), R261Q (1.6%), Y414C (1.0%) and I65T (0.5%). Mutations that have been predominantly described in southern Europe (IVS7nt1, A259V, Y277D, R241H, T278N) were not detected. A total of 14 different mutant haplotypes were observed. Three unusual genotype-haplotype associations were identified (R158Q on haplotypes 2.3 and 7.8 and R252W on haplotype 69.3). There was a strong association between the mutation R408W and haplotype 2.3 (54.7%). Heterogeneity was found at mutations R408W (haplotypes 2.3 and 5.9), R158Q (haplotypes 4.3, 2.3 and 7.8) and IVS10nt546 (haplotypes 6.7 and 34.7). The molecular basis of PKU in the Moravian area appears to be relatively homogeneous in comparison with other southern and western European populations, thus providing a good starting point for prenatal diagnosis and early clinical classification.

A Case of a Novel PML/RARA Short Fusion Transcript with Truncated Transcription Variant 2 of the RARA Gene

Acute promyelocytic leukemia (APL) with atypical breakpoints in the promyelocytic leukemia (PML) and retinoic acid receptor-α (RARA) genes represents a rare leukemic event, which occurs preferentially in patients with variant types of the PML/RARA fusion gene. Here we report on a patient with APL with a unique PML/RARA fusion transcript that harbors a short type of this fusion gene, exhibiting unexpected results of standard PCR diagnostics. The detected transcript originates from fusion of PML exon 4 and a truncated form of transcription variant 2 of the RARA gene, with an additional 9 bp insertion. According to our knowledge, this differs from all previously described fusion transcripts.

CEBPA gene mutational status: a complete screening using high-resolution melt curve analysis.

In recent years, several independent prognostic factors in cytogenetically normal acute myeloid leukemia (CN-AML) have been reported. Mutations or the expression levels of certain genes have been often used as molecular markers for prediction of a patients outcome or for evaluation of treatment outcome. One of them, the gene encoding CCAAT/enhanced binding protein alpha (CEBPA), plays an important role in myeloid differentiation and, when mutated, confers a favorable prognosis for patients with CN-AML. Complete mutation screening of the CEBPA gene is therefore beneficial and requires fast, precise, and sensitive diagnostic tools. Thus, for routine diagnostics, we developed a screening method using high-resolution melt curve analysis prior to direct sequencing, where only positive samples (according to reference) are further sequenced. With this approach, all positive and negative patients were successfully distinguished, and the results obtained were in absolute concordance with the direct sequence analysis.

CEBPA Gene Mutational Status

In recent years, several independent prognostic factors in cytogenetically normal acute myeloid leukemia (CN-AML) have been reported. Mutations or the expression levels of certain genes have been often used as molecular markers for prediction of a patient’s outcome or for evaluation of treatment outcome. One of them, the gene encoding CCAAT/enhanced binding protein alpha (CEBPA), plays an important role in myeloid differentiation and, when mutated, confers a favorable prognosis for patients with CN-AML. Complete mutation screening of the CEBPA gene is therefore beneficial and requires fast, precise, and sensitive diagnostic tools. Thus, for routine diagnostics, we developed a screening method using high-resolution melt curve analysis prior to direct sequencing, where only positive samples (according to reference) are further sequenced. With this approach, all positive and negative patients were successfully distinguished, and the results obtained were in absolute concordance with the direct sequence analysis.

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.

Erdheim-Chester disease and Schnitzler syndrome: so near, and yet so far.

A 56-year-old male presented with diabetes insipidus, noninfectious fever, night sweats, and pain in both lower legs and pelvis. Developing gradually over a period of 9 years, these symptoms were accompanied by increased acute phase markers (C-reactive protein = 63 mg/L, erythrocyte sedimentation rate = 52 mm/h and 72 mm/2 h, fibrinogen = 6.5 g/L). Technetium-99m pyrophosphate bone scintigraphy showed abnormal tracer uptake predominantly in the long bones of the lower extremities, with additional hot spots in the skull, right shoulder, left humerus, and both radial bones (Fig. 1). Positron emission tomography (PET) identified a similar pattern of 18F-fluorodeoxyglucose uptake correlating with osteosclerotic lesions on conventional radiography (X-ray) and computed tomography(CT). Subsequently, histological findings of CD68- and S100-positive, CD1a-negative foamy histiocytes from a bone biopsy were compatible with Erdheim–Chester disease. Moreover, the obtained tissue samples were positive for BRAF V600E mutation on CE-IVD validated BRAF 600/601 StripAssay (ViennaLab Diagnostics GmbH, Austria).

Evaluation of 5-year imatinib treatment of 458 patients with CP-CML in routine clinical practice and prognostic impact of different BCR-ABL cutoff levels

We evaluated responses to the treatment and long‐term outcomes of chronic myeloid leukemia patients treated with imatinib as first‐line treatment in routine clinical setting from two countries with centralized tyrosine kinase inhibitors (TKIs) treatment. We assessed prognostic significance of European LeukemiaNet (ELN) 2006‐ and 2009‐defined responses and the prognostic value of molecular responses at defined time points on 5‐year survivals. Among the cumulative rates of incidence of hematologic, cytogenetic, and molecular responses and all important survival parameters, we evaluated the prognostic significance of different BCR‐ABL transcript‐level ratios (≤1%; >1%–≤10%; >10%) at 3, 6, 12, and 18 months (n = 199). The ELN optimal response criteria and their predictive role were significantly beneficial for event‐free survival at all given time points. We found significant improvement in survivals of patients with BCR‐ABL lower than 10% in the 6th and 12th months. Significantly better outcome was found in patients who achieved major molecular response (MMR) in the 12th month. The cumulative incidences of complete cytogenetic response (CCyR) and MMR were significantly associated with the molecular response in the 3rd month. The ELN response criteria and their predictive role were helpful at given time points; however, the 2009 definition did not significantly alter the prognostic accuracy compared with that of the 2006 definition. The significant value was observed for cytogenetic responses at the 6th and 12th month. Moreover, progression‐free and event‐free survivals were improved with MMR at the 12th month.

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.