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Introduction: The identification of patients with essential thrombocythemia (ET) who are at increased risk of acquired von Willebrand syndrome (AVWS) would likely facilitate individualization of treatment and improve its outcomes., Objectives: The aim of the study was to determine the prevalence of AVWS in patients with ET and to verify whether individuals with and without this bleeding disorder differ in terms of their baseline clinical parameters., Patients and Methods: The study included 170 consecutive patients with ET. AVWS was diagnosed on the basis of reduced levels of von Willebrand factor and abnormal results of other routine tests. Patients with and without concomitant AVWS were compared in terms of their demographic characteristics, past and current medical histories, and laboratory parameters., Results: Concomitant AVWS was found in 34 patients (20%). Individuals with AVWS were diagnosed with ET at a significantly younger age than those without the syndrome. In addition, these patients significantly less often were in remission at the time of testing, had significantly higher erythrocyte and platelet counts, and showed abnormalities of the coagulation profile corresponding to defects of primary hemostasis as well as abnormal values of most parameters used i n the routine diagnosis of AVWS., Conclusions: Even every fifth patient with ET may develop AVWS. Young age at diagnosis of ET and the lack of response to its previous treatment are potential risk factors for AVWS that should be considered during the management of the primary condition. All patients with ET and signs of a bleeding disorder, irrespective of the platelet count, should be tested for the presence of AVWS.

Introduction: The presence of BCR-ABL oncogene mutations in patients with chronic myeloid leukemia (CML) may be responsible for the failure of tyrosine kinase inhibitor treatment., Objectives: The aim of the study was to evaluate the frequency of BCR-ABL gene mutations in patients with CML (the MAPTEST study) treated with imatinib (IM)., Patients and Methods: Direct sequencing analysis of BCR-ABL gene was performed in 92 patients treated with IM for more than 3 months. The mean time of IM treatment was 18 months. At the time of the analysis, 75 patients were in the first chronic phase (CP), 4 in the second CP, 5 in the acceleration and 8 in the blastic phase. Fifty-seven patients (62%) were treated with IM at a daily dose of 400 mg and 35 patients with higher doses (600 or 800 mg daily). Inclusion criteria were based on the European Leukemia Net definitions for failure and suboptimal response to IM., Results: Twelve mutations were detected in 11 of 92 patients, including 4 mutations (36.7%) diagnosed during CP, 3 (27.3%) in acceleration, and 4 (36.7%) in blast crisis. In 1 patient with lymphoid blast crisis of CML coexisting F359V and Y253F mutations were detected. In the whole group mutations were detected in 2 of 5 patients (40%) with primary resistance (M351T, F359V + Y253F) and in 9 of 87 patients (10.3%) (E255K, T315I-3x, M351T, E355G, F359V-2x) with acquired resistance to IM., Conclusions: The study confirmed the usefulness of BCR-ABL gene mutation screening in patients with CML resistant to IM therapy.