Objective: Mutations of the nucleophosmin (NPM1) gene are considered as the most frequent acute myeloid leukemia (AML)-associated genetic lesion, reported with various incidences in different studies, and type A (NPM1-A) is the most frequent type. However, since most series in the literature report on the features of all patients regardless of the type of mutation, NPM1-A(+) cases have not been well characterized yet. Therefore, we evaluated the prevalence of NPM1-A in Bulgarian AML patients and searched for an association with clinical and laboratory features. Materials and Methods: One hundred and four adults (51 men, 53 women) were included in the study. NPM1-A status was determined using allele-specific reverse-transcription polymerase chain reaction with co-amplification of NPM1-A and β-actin and real-time quantitative TaqMan-based polymerase chain reaction. Patients received conventional induction chemotherapy and were followed for 13.2±16.4 months.Results: NPM1-A was detected in 26 (24.8%) patients. NPM1-A mutation was detected in all AML categories, including in one patient with RUNX1-RUNX1T1. There were no differences associated with the NPM1-A status with respect to age, sex, hemoglobin, platelet counts, percentage of bone marrow blasts, splenomegaly, complete remission rates, and overall survival. NPM1-A(+) patients, compared to NPM1-A(-) patients, were characterized by higher leukocyte counts [(75.4±81.9)x109/L vs. (42.5±65.9)x109/L; p=0.049], higher frequency of normal karyotype [14/18 (77.8%) vs. 26/62 (41.9%); p=0.014], higher frequency of FLT3-ITD [11/26 (42.3%) vs. 8/77 (10.4%); p=0.001], and lower incidence of CD34(+) [6/21 (28.8%) vs. 28/45 (62.2%); p=0.017]. Within the FLT3-ITD(-) group, the median overall survival of NPM1-A(-) patients was 14 months, while NPM1-A(+) patients did not reach the median (p=0.10). Conclusion: The prevalence of NPM1-A mutation in adult Bulgarian AML patients was similar to that reported in other studies. NPM1-A(+) patients were characterized by higher leukocyte counts, higher frequency of normal karyotypes and FLT3-ITD, and lower incidence of CD34(+), supporting the idea that the specific features of type A mutations might contribute to the general clinical and laboratory profile of NPM1(+) AML patients.

Chronic myeloid leukemia (CML) is one of the most common hematological malignancies and accounts for 15-20% of all leukemia cases. The cytogenetic marker of CML is the presence of Philadelphia chromosome (Ph) in >95% of patients. The current case reports a 83-year old woman who was directed to the genetic laboratory for a cytogenetic and molecular-genetic analysis suspected to be Ph positive [(+)]. Karyotype analysis of a bone marrow sample revealed a hyperdiploid karyotype in a part of Ph (+) cells with additional chromosomes 8, 10 and 12. Restriction analysis for V617F JAK2 mutation was negative, while the quantitative RT-qPCR assay indicated BCR-ABL/ABL transcript at the level of 120% International Scale (IS). Generally cytogenetic complexities are important in the prognostic evaluation of CML. Besides the Ph chromosome, a variet of chromosomal aberrations may be associated with CML. A total of 5-10% of these cases show complex translocations involving another chromosome. The current case is Ph(+) demonstrating an additional hyperdiploid karyotype clone with three additional autosomes (8, 10 and 12). This case highlights the significance of cytogenetic abnormalities on the prognosis of CML.

No abstract

Background: V617F JAK2 mutation is a typical molecular finding in BCR-ABL-negative myeloproliferative neoplasms (MPN). The same abnormality has also been reported in other myeloid malignancies. However, the data regarding the incidence and clinical relevance of V617F JAK2 in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are conflicting. Aim: To establish the incidence and clinical significance of V617F JAK2 mutation in AML and MDS patients in our institution. Materials and Methods : AML and MDS patients with isolated bone marrow mononuclear cells were included in this study, as follows: (i) 139 AML patients (71 females; 68 males; mean age of 57.5±15.3 years), including: 122 - de novo AML, 7 - therapy related AML (t-AML) and 10 - secondary AML (sAML) after primary MPN [3 V617F JAK2(+), 2 V617F JAK2(-) and 5 with unknown initial V617F JAK2 status]; (ii) 35 MDS patients. V617F JAK2 mutation status was determined using allele-specific polymerase chain reaction (PCR) and PCR RFLP (Restriction Fragment Lenght Polymorphism) analysis. Results: V617F JAK2 mutation was detected in 3 AML patients: (i) in 1/122 (0.8%) de novo AML patients - male patient with minimally differentiated AML, with no antecedent MPN and the leukemic population showed aberrant myeloid phenotype with co-expression of CD7 and overexpression of EVI1 gene, (ii) in 2/10 (20.0%) patients with sAML after MPN and both patients had V617F JAK2(+) sAML after V617F JAK2(+) primary myelofibrosis. Interestingly; in the same group, a female patient with V617F JAK2(+) essential thrombocythemia developed 5 years later V617F JAK2(-) sAML with an aberrant myelomonocytic phenotype and co-expression of CD56. None of the patients with t-AML or MDS tested positive for V617F JAK2. Conclusion: V617F JAK2 mutation is a rare finding in AML and MDS patients. Higher incidence was observed in sAML after MPN. However, the mutation status at the AML stage may not be identical as that detected during the primary MPN. Disclosures No relevant conflicts of interest to declare.