Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy associated with various combinations of gene mutations, epigenetic abnormalities, and chromosome rearrangement-related gene fusions. Despite the significant degree of heterogeneity in its pathogenesis, many gene fusions and point mutations are recurrent in AML and have been employed in risk stratification over the last several decades. Gene fusions have long been recognized for understanding tumorigenesis and their proven roles in clinical diagnosis and targeted therapies. Advances in DNA sequencing technologies and computational biology have contributed significantly to the detection of known fusion genes as well as for the discovery of novel ones. Several recurring gene fusions in AML have been linked to prognosis, treatment response, and disease progression. In this report, we present a case with a long history of essential thrombocythemia and hallmark CALR mutation transforming to AML characterized by a previously unreported AKAP9::PDGFRA fusion gene. We propose mechanisms by which this fusion may contribute to the pathogenesis of AML and its potential as a molecular target for tyrosine kinase inhibitors.

Acquired von Willebrand syndrome (AVWS) is a rare bleeding disorder that is often underdiagnosed. AVWS typically occurs in adults without a family history of bleeding disorders and with associated conditions such as lymphoproliferative, myeloproliferative, and cardiovascular disorders. Here, we present a case of AVWS in a young patient with essential thrombocythemia and a literature review on AVWS in the setting of essential thrombocythemia.

The classical myeloproliferative neoplasms are divided into chronic myeloid leukemia, and the Philadelphia negative polycythemia vera, essential thrombocythemia and primary myelofibrosis. These are heterogenous diseases, originating from the clonal proliferation of myeloid stem cells, resulting in increased mature cell numbers in one or more myeloid lineages. The most commonly seen mutations in the Philadelphia negative myeloproliferative neoplasms include those in Janus kinase, myeloproliferative leukemia protein and the calreticulin genes. Philadelphia negative myeloproliferative neoplasms occur infrequently, with a combined annual incidence of 2.58 per 100,000. There are many overlapping symptoms of Philadelphia negative MPNs, such as fatigue, night sweats, hepatosplenomegaly and circulatory symptoms due to increased cell numbers. Total Symptom Score of the MPN Symptom Assessment Form is used to assess symptom burden on patients. The most worrisome complications are thrombo-hemorrhagic events, and risk stratification is especially important as treatment of disease is based on their category. Phlebotomy and aspirin are the mainstay of treatment in low-risk polycythemia vera and essential thrombocythemia patients, whereas high-risk disease calls for additional cytoreduction, usually with hydroxyurea.

Thrombotic events are the most frequent manifestations of essential thrombocythemia (ET). The objective of this study is to determine the incidence of thrombosis at different sites on follow-up in patients with ET. We searched PubMed, Web of Science, and The Cochrane Library databases and calculated the incidence of thrombosis by pooling and analyzing the extracted data using a random-effects model. A total of 70 studies (N  =  25,805) were included in the analysis. The total and annual incidences of arterial thrombosis on follow-up were 13.4% and 2.0%, respectively. The total and annual incidences of the different manifestations of arterial thrombosis were as follows: stroke (5.3% and 0.8%), transient ischemic attack (5.1% and 1.2%), myocardial infarction (2.4% and 0.5%), unstable angina (0.9% and 0.2%), and peripheral arterial thrombosis (2.0% and 0.2%), respectively. In contrast, the total and annual incidences of arterial thrombosis in JAK2-positive patients were 18.4% and 2.7%, respectively. The total and annual incidences of arterial thrombosis in JAK2-negative patients were 5.9% and 0.8%, respectively. The total and annual incidences of venous thrombosis were 5.5% and 0.7%, respectively, and the incidences of the different manifestations of venous thrombosis at different sites were as follows: peripheral venous thrombosis (2.9% and 0.5%), superficial venous thrombosis (1.8% and 0.7%), deep venous thrombosis (1.6% and 0.3%), abdominal venous thrombosis (0.8% and 0.1%), pulmonary embolism (0.3% and 0.1%), and cerebral venous thrombosis (0.2% and 0%), respectively. The total and annual incidences of venous thrombosis in JAK2-positive patients were 7.4% and 1.2%, respectively. The total and annual incidences of venous thrombosis in JAK2-negative patients were 1.6% and 0.4%, respectively. The incidence of arterial thrombosis was higher than that of venous thrombosis in patients with ET. Arterial thrombosis manifested with cerebral arterial thrombosis, followed by cardiac thrombosis. Venous thrombosis events were mainly peripheral and superficial venous thrombosis. JAK2-positive patients have a higher incidence of arterial and venous thromboses than JAK2-negative patients, the sequence of thrombsis sites was similar to that of the overall patients.

Aspirin inhibits platelet function by irreversibly inhibiting the synthesis of thromboxane A2 (TxA2). Aspirin, at low doses, is widely used for cardiovascular prevention. Gastrointestinal discomfort, mucosal erosions/ulcerations and bleeding are frequent complications of chronic treatment. To reduce these adverse effects, different formulations of aspirin have been developed, including enteric-coated (EC) aspirin, the most widely used aspirin formulation. However, EC aspirin is less effective than plain aspirin in inhibiting TxA2 production, especially in subjects with high body weight. The inadequate pharmacological efficacy of EC aspirin is mirrored by lower protection from cardiovascular events in subjects weighing >70 kg. Endoscopic studies showed that EC aspirin causes fewer erosions of the gastric mucosa compared to plain aspirin (which is absorbed in the stomach) but causes mucosal erosions in the small intestine, where it is absorbed. Several studies demonstrated that EC aspirin does not reduce the incidence of clinically relevant gastrointestinal ulceration and bleeding. Similar results were found for buffered aspirin. Although interesting, the results of experiments on the phospholipid-aspirin complex PL2200 are still preliminary. Considering its favorable pharmacological profile, plain aspirin should be the preferred formulation to be used for cardiovascular prevention.

Myeloproliferative neoplasms (MPNs) are defined as clonal disorders of the hematopoietic stem cell in which an exaggerated production of terminally differentiated myeloid cells occurs. Classical, Philadelphia-negative MPNs, i.e., polycythemia vera, essential thrombocythemia and primary myelofibrosis, exhibit a propensity towards the development of thrombotic complications that can occur in unusual sites, e.g., portal, splanchnic or hepatic veins, the placenta or cerebral sinuses. The pathogenesis of thrombotic events in MPNs is complex and requires an intricate mechanism involving endothelial injury, stasis, elevated leukocyte adhesion, integrins, neutrophil extracellular traps, somatic mutations (e.g., the V617F point mutation in the JAK2 gene), microparticles, circulating endothelial cells, and other factors, to name a few. Herein, we review the available data on Budd-Chiari syndrome in Philadelphia-negative MPNs, with a particular focus on its epidemiology, pathogenesis, histopathology, risk factors, classification, clinical presentation, diagnosis, and management.

OBJECTIVE: The WHO 2016 re-classification of myeloproliferative neoplasms resulted in a separation of essential thrombocythemia (ET) from the pre-fibrotic and fibrotic (overt) phases of primary myelofibrosis (MF). This study reports on a chart review conducted to evaluate the real life approach regarding clinical characteristics, diagnostic assessment, risk stratification and treatment decisions for MPN patients classified as ET or MF after implementation of the WHO 2016 classification.
METHODS: In this retrospective chart review, 31 office-based hematologists/oncologists and primary care centers in Germany participated between April 2021 and May 2022. Physicians reported available data obtained from patient charts via paper-pencil based survey (secondary use of data). Patient features were evaluated using descriptive analysis, also including diagnostic assessment, therapeutic strategies and risk stratification.
RESULTS: Data of 960 MPN patients diagnosed with essential thrombocythemia (ET) (n = 495) or myelofibrosis (MF) (n = 465) after implementation of the revised 2016 WHO classification of myeloid neoplasms was collected from the patient charts. While they met at least one minor WHO-criteria for primary myelofibrosis, 39.8% of those diagnosed with ET did not have histological BM testing at diagnosis. 63.4% of patients who were classified as having MF, however, did not obtain an early prognostic risk assessment. More than 50% of MF patients showed characteristics consistent with the pre-fibrotic phase, which was emphasized by the frequent use of cytoreductive therapy. Hydroxyurea was the most frequently used cytoreductive medication in 84.7% of ET and 53.1% of MF patients. While both ET and MF cohorts showed cardiovascular risk factors in more than 2/3 of the cases, the use of platelet inhibitors or anticoagulants varied between 56.8% in ET and 38.1% in MF patients.
CONCLUSIONS: Improved histopathologic diagnostics, dynamic risk stratification including genetic risk factors for cases of suspected ET and MF are recommended for precise risk assessment and therapeutic stratification according to WHO criteria.

The impact of primary arterial hypertension (HTN) in myeloproliferative neoplasms (MPNs) remains unclear, with scant literature available, mostly focusing on cardiovascular risk factors as a singular entity or on organ-specific HTN. Furthermore, available studies reporting findings on drug-induced HTN in MPNs report varying and contradictory findings. In consideration of the above, this study set out to systematically review the available literature and shed light on the occurrence of HTN in MPNs, its association with thrombosis, as well as the drugs used in MPN management that could increase blood pressure. The literature search yielded 598 potentially relevant records of which 315 remained after the duplicates (n = 283) were removed. After we screened the titles and the abstracts of these publications, we removed irrelevant papers (n = 228) and evaluated the full texts of 87 papers. Furthermore, 13 records did not meet the inclusion criteria and were excluded from the systematic review. Finally, a total of 74 manuscripts were entered into the qualitative synthesis and included in the present systematic review. Our systematic review highlights that HTN is the most common comorbidity encountered in MPNs, with an impact on both the occurrence of thrombosis and survival. Moreover, drug-induced HTN remains a challenge in the management of MPNs. Further research should investigate the characteristics of patients with MPNs and HTN, as well as clarify the contribution of HTN to the development of thrombotic complications, survival and management in MPNs. In addition, the relationship between clonal hematopoiesis of indeterminate potential, HTN, cardiovascular disease and MPNs requires examination in upcoming assessments.

BACKGROUND: Philadelphia-negative myeloproliferative neoplasms (MPN) are most prevalent in the older population (median age at the diagnosis is above 60 years) and rarely diagnosed in pediatrics. Thus, our knowledge about the clinical presentation, mutational status, and complications of MPNs in pediatrics is limited.
METHODS: The literature in English (PubMed, SCOPUS, and Google Scholar) was searched for studies, reviews, case series, and case reports of patients with Philadelphia-negative MPNs (including essential thrombocythemia, polycythemia vera, primary myelofibrosis, and profibrotic myelofibrosis) in the pediatrics age group (less than 18 years). Only studies that fulfilled WHO 2008 or 2016 criteria for MPNs were included. We aimed to describe the clinical characteristics, vascular and long-term complications, types of driver mutations, and treatment approaches in pediatric patients with MPNs.
RESULTS: We reviewed 33 articles of available published literature from 2008 to 2022 and collected data from a total of 196 patients of the pediatric population. Among the cohort of patients, 139 had essential thrombocythemia (ET), 20 had polycythemia vera (PV), and 37 had primary myelofibrosis (PMF). The median age at the time of diagnosis for each disease varied, with 8.8 years for ET, 10 years for PV, and 3.6 years for MF. There was a slight difference in gender prevalence between both gender groups and all three diseases. The presenting symptoms were not mentioned in more than 50% of studies. We found that JAK2 was the most prevalent among all mutations. Both bleeding and thrombosis were present equally in ET, with 9% of cases complicated by bleeding and 9% complicated by thrombosis. Hemorrhagic events did not occur in patients with PV; thrombosis in children with MF was also not found. The progression into AML occurred in two patients with PV and one with ET.
CONCLUSIONS: Given the rarity of MPNs in pediatrics and their different characteristics compared with adults, we believe there is a need for unique diagnostic criteria to match the different molecular statuses in pediatrics. Based on our review, the incidence of MPN complications in pediatrics, including thrombotic events, hemorrhage, and leukemic transformation, differs from that in adults.

BACKGROUND: Secondary hypertension, e.g., drug-induced hypertension (DI-HTN), can occur in patients with solid/hematological cancers. However, the relationship between anticancer therapy and DI-HTN in classical Philadelphia-negative MPNs is unclear.
OBJECTIVE: Investigate this research question via a systematic review.
METHODS: Comprehensive search in PubMed/MEDLINE, SCOPUS and Web of Science. Publications that reported DI-HTN as an adverse effect (AE) of anticancer therapy for MPNs were included in the qualitative/quantitative synthesis.
RESULTS: Search strategy identified 590 records. After removal of duplicates/screening of titles/abstracts, 87 papers were selected for full-text review. After inclusion/exclusion criteria were applied, 12 manuscripts entered into the qualitative/quantitative synthesis. Ruxolitinib\'s effect (RUX) on systolic (SBP)/diastolic (DBP) blood pressure is controversial: one study reported no effect on SBP/DBP, whereas in another SBP but not DBP increased. In RESPONSE-2 trial, DI-HTN developed as non-hematological AE [grade 3-4 (6%, n=5); grade 1-2 (3%, n=2)] in 9% (n=7) of 74 polycythemia vera (PV) patients enrolled. RESPONSE-2 secondary analyses reported RUX-induced hypertension as the most frequent grade 3/4 AE in the RUX/RUX cross-over arms. Interferon did not cause DI-HTN in RESPONSE and RESPONSE-2 trials. RUX+decitabine in accelerated/blast phase MPNs (n=25) caused 3 DI-HTN cases: grade 1/2 (n=2), grade 3+ AE (n=1). RUX+decitabine resulted in 2 DI-HTN cases (grade 3 AE in 21 MPNs in accelerated/blast phase). RUX+danazol in 14 primary/secondary myelofibrosis (PMF/SMF) subjects lead to 1 DI-HTN case (n=1, 7.1%) in a multicentric phase 2 study. Anagrelide caused DI-HTN as AE in 9 essential thrombocythemia (ET) subjects, however, hydroxyurea caused DI-HTN in 1 of 146 patients. Italian ET registry retrospective evaluation reported DI-HTN in 3.5% (n=8) of 232 anagrelide-treated subjects. DI-HTN occurred as dose-limiting toxicity in an open-label, dose-escalation assessment of AT9283 (Aurora kinases inhibitor) in advanced PMF/SMF and refractory AML. Givinostat caused DI-HTN (grade 3 AE) in 1 of 50 PV subjects.
CONCLUSIONS: RUX (alone/in combination with decitabine/danazol), anagrelide, AT9283, and givinostat can cause DI-HTN in classical Philadelphia-negative MPNs.