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Introduction. MicroRNAs (miRNAs) are small non-coding single-stranded RNA molecules that regulate gene expression at the post-transcriptional level. In the pathogenesis of chronic lymphocytic leukemia (CLL), miR-15a and miR-16-1 play an important role. These miRNAs are located on chromosome 13 in the 13q14.3 region, which is deleted in more than 55% of CLL patients. This aberration affects expression of miRNAs. Objectives. The study aimed at performing a molecular genetic analysis of miR-15a and miR-16-1 expression in a group of 39 patients diagnosed with CLL and determining the association between the expression of the two miRNAs and types of deletions in the 13q14 region. Methods. We used fluorescence in situ hybridiziation (FISH) for determination of mono- or biallelic deletion 13q and quantitative polymerase chain reaction (Q-RT-PCR) to revealed expression miR-15a and miR-16-1 in 39 patients suffering from CLL. Results. The analysis comprised 19 patients with monoallelic 13q14 deletion, 3 patients with biallelic deletion, 9 patients with both monoallelic and biallelic deletions, and 8 patients without 13q14 deletion serving as controls. The results showed different levels of miRNA expression in individual patients. Significantly higher normalized levels of miR-15a expression were found in the control group and patients with monoallelic 13q14 expression compared with patients with biallelic deletion. There was a significantly decreased expression of both miRNAs in patients with biallelic deletion of the 13q14 region but only when deletions were present in 77% or more of cells, as detected by fluorescent in situ hybridization (FISH).

Aims. We assessed the long-term outcome of consecutive patients in the chronic phase of chronic myeloid leukemia (CML) treated with interferon-alpha (INF-α) in Central and Northern Moravia between 1989 and 2006. Methods. A retrospective study focused on the response, prognostic factors and side-effects of INF-α. Results. 118 patients (67 males and 51 females, median age 50 years; range 18-71) were analyzed. The median followup was 82.6 months (12.4-212.6). Thirty-six patients (30.5%) achieved major cytogenetic response (CyR) in median of 18.3 months (3.7-47.3) and maintained it for a median of 64.0 months (7.0-176.0). Sixty-one patients treated with INF-α for more than 12 months had an overall survival (OS) of 137.0 months (95% CI 117.6-156.4). Eighteen (29.5%) achieved complete CyR (CCyR). 109 patients discontinued the treatment with INF-α because of hematologic or cytogenetic resistance in 53 (48.7%), progression of CML in 31 (28.4%) and intolerance to INF-α in 17 (15.6%) patients. The percentage of peripheral blasts, leukocyte count (>50x10 9 /L), splenomegaly, anemia (Hgb≤110 g/L) and Sokal score had statistical impact on the OS in univariate assessment but only the Sokal score remained significant in multivariate analysis. Additional cytogenetic abnormalities at diagnosis were associated with poor prognosis. Conclusions. In most patients, treatment with INF-α had to be stopped because of a failure to induce response, progression of CML or side-effects but nearly one third of patients treated at least for one year had a long-term benefit from INF-α. The best prognosis was associated with achievement of CCyR and negativity of BCR-ABL in nested RT-PCR.

Background. The Recommendations of the European Leukemia Net (ELN) have become an essential tool in the management and prognosis of patients with chronic myeloid leukemia (CML) treated with tyrosine kinase inhibitors (TKIs). However, the definition of suboptimal response remains under discussion. Methods. We used conventional cytogenetics for the detection of clonal changes in Ph-positive and negative clones. RT-PCR and sequencing were carried out on peripheral blood leukocytes to detect the type of BCR-ABL1 transcript. The BCR-ABL1 mutational status was assessed using sequencing of RT-PCR products. High performance capillary electrophoresis for determination of imatinib (IMA) plasma concentration was used. Results. A retrospective study of 110 patients diagnosed with chronic-phase (CP) CML treated with IMA or 2 nd generation TKIs in the years 2000-2009 focused on analysis of patients with suboptimal response according to ELN criteria. 40 patients were administered IMA as first-line therapy and 70 had been pretreated with interferon-alpha (IFN-α) with or without Ara-C and/or hydroxyurea (HU) for a median 12 months (range, 1-92 months). After adjusting for the ELN criteria, major molecular response (MMR) was achieved after median 34 and 39 months in 66.7% and 41.7% of patients after the first and second-line IMA therapy with suboptimal response defined as lack of achievement of MMR at the 18 th month of treatment, respectively. In comparison to patients with optimal response, patients with suboptimal response did not show significant differences in overall survival (OS) or progression-free survival (PFS). Cytogenetic assays demonstrated additional chromosome abnormalities (ACAs): chromosome 8 trisomy in a Ph-negative clone during the IMA treatment (in 1 case) and der(9q) in Ph-positive clone (in 2 cases); in patients receiving first-line IMA only chromosome 8 trisomy was observed which was associated with myelodysplastic syndrome – this was the only case where hematopoietic stem cell transplantation (HSCT) was performed. During the treatment with IMA in both subgroups no regulatory mutations in the ABL kinase domain were confirmed. Conclusion. We believe that the category of suboptimal response should be redefined or withdrawn from the ELN 2009 recommendations for management of CML patients treated with TKIs. Patients with suboptimal response who have no additional risks (additional cytogenetic abnormalities or BCR-ABL1 regulatory mutations) may remain on IMA treatment while patients with these risks should be switched to the 2 nd generation TKIs.

Aim. This is a case report of a 51 year old male with marked splenomegaly, basophilia, severe thrombocytopenia, anemia and high SFKL phosphorylation downstream of Bcr-Abl, investigated for association of the e6a2 BCR-ABL fusion gene and marked basophilia. The treatment strategy implications in patients with Philadelphia positive CML are described. Methods. RT-PCR and sequencing were carried out on the peripheral blood leukocytes to detect the type of BCRABL transcript. The BCR-ABL mutational status was assessed using sequencing of the RT-PCR products. The in vitro test of sensitivity to TKIs was based on detecting inhibited phosphorylation of the Crkl and Phospho-Src family kinases (SFK, Tyr416) using immunodetection. Results. The cytogenetics revealed 90% of Ph+ (Philadelphia) cells in the bone marrow aspirate with no additional clonal chromosomal abnormalities at diagnosis. This correlated with an accelerated phase of the CML. Sequencing analysis of reverse transcribed and PCR amplified BCR-ABL transcript revealed a rare e6a2 fusion, with no evidence for Bcr-Abl kinase domain mutation. Western blot analysis showed high phosphorylation (activation) of Crkl and the Src family of kinases (P-SFK). In vitro test of sensitivity of the patients’ leukemic cells to imatinib demonstrated sensitivity of Bcr-Abl tyrosine kinase to imatinib, as assessed by a decrease in phosphorylated Crkl and the disappearance of P-SFK, suggesting that P-Src reflects only the Bcr-Abl–dependent Src activity. The initial treatment strategy was reduced imatinib and search for an unrelated hematopoietic stem cell donor (according to the ELN recommendations). The patient was allografted with peripheral stem cells from an HLA- identical male donor but on day +70 graft failure occurred. He was allografted again with the peripheral stem cells from an HLA-identical female donor, engrafted on day +15 and showed 100% donor chimerism with no evidence of the e6a2 BCR-ABL fusion transcript on day +30. Conclusion. The clinical disease course in patients with the rare e6a2 BCR-ABL transcript variant is aggressive. This may be the result of increased kinase activity due to partial loss of the guanine exchange factor/dbl-like domain which mediates the interaction with several Ras-like G-proteins involved in cell proliferation, signal transduction, and cytoskeletal organization. For the above reasons, these patients should receive stem cell transplant immediately after a short course of treatment with imatinib/ dual Src/Abl kinase inhibitor or they should be registered in clinical trials with experimental agents.

To report a case of successful pregnancy in a patient with chronic myelogenous leukemia treated with imatinib mesylate for the first 4 months of pregnancy.Imatinib mesylate is potentially teratogenic and its use during pregnancy in humans can lead to abortion or development of fetal abnormalities in nearly 40% of fully reported cases. We report a case of a 28-year-old woman who delivered a healthy child of normal weight after having been treated with imatinib for Ph1-positive CML during the first four months of her pregnancy. She refused advocated interruption and for the rest of the pregnancy was treated with interferon. The treatment was associated with a rapid 2-log increase in the leukemia clone measured by the real-time polymerase chain reaction. Reintroduction of imatinib after delivery resulted in achievement of the complete cytogenetic response again.We discuss possible strategies for successful management of pregnancy in CML patients treated with imatinib.

T-cell gamma/delta hepatosplenic lymphoma is a primary extranodal lymphoma, distinct from other T/LGL lymphomas. The clinical course is aggressive, and despite use of the multiagent chemotherapy and young age of the patients, the median survival is less than 1 year. Curability of this disease is still uncertain. We reported a case of the successful intensive treatment with splenectomy, chemotherapy a first line autologous stem cell transplant. High intensity cytarabine- platinum containing regimen (EDHAP) may overcome primary resistance to conventional alkylating agents.