Primary myelofibrosis is the most frequent myeloproliferative neoplasm associated with del(5q): clinicopathologic comparison of del(5q)-positive and -negative cases

Myeloproliferative Neoplasms, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

The classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) consist of myelofibrosis, polycythemia vera, and essential thrombocythemia and are a heterogeneous group of clonal blood disorders characterized by an overproduction of blood cells. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for MPN were developed as a result of meetings convened by a multidisciplinary panel with expertise in MPN, with the goal of providing recommendations for the management of MPN in adults. The Guidelines include recommendations for the diagnostic workup, risk stratification, treatment, and supportive care strategies for the management of myelofibrosis, polycythemia vera, and essential thrombocythemia. Assessment of symptoms at baseline and monitoring of symptom status during the course of treatment is recommended for all patients. This article focuses on the recommendations as outlined in the NCCN Guidelines for the diagnosis of MPN and the risk stratification, management, and supportive care relevant to MF.

The Prognostic Role of Cytogenetics Analysis in Philadelphia Negative Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) are clonal stem cell disorders characterized collectively by clonal proliferation of myeloid cells with variable morphologic maturity and hematopoietic efficiency. Although the natural history of these neoplasms can be measured sometimes in decades more than years, the cytogenetics analysis can offer useful information regarding the prognosis. Cytogenetics has a well-established prognostic role in acute leukemias and in myelodysplastic syndromes, where it drives the clinical decisions. NGS techniques can find adverse mutations with clear prognostic value and are currently included in the prognostic evaluation of MPNs in scores such as MIPSS, GIPSS, MIPSS-PV, and MIPSS-ET. We suggest that cytogenetics (considering its availability and relative cost) has a role regarding prognostic and therapeutic decisions.

Genetic Alterations in Essential Thrombocythemia Progression to Acute Myeloid Leukemia: A Case Series and Review of the Literature

The genetic events associated with transformation of myeloproliferative neoplasms (MPNs) to secondary acute myeloid leukemia (sAML), particularly in the subgroup of essential thrombocythemia (ET) patients, remain incompletely understood. Deep studies using high-throughput methods might lead to a better understanding of genetic landscape of ET patients who transformed to sAML. We performed array-based comparative genomic hybridization (aCGH) and whole exome sequencing (WES) to analyze paired samples from ET and sAML phases. We investigated five patients with previous history of MPN, which four had initial diagnosis of ET (one case harboring JAK2 p.Val617Phe and the remaining three CALR type II p.Lys385fs*47), and one was diagnosed with MPN/myelodysplastic syndrome with thrombocytosis (SF3B1 p.Lys700Glu). All were homogeneously treated with hydroxyurea, but subsequently transformed to sAML (mean time of 6 years/median of 4 years to transformation). Two of them have chromosomal abnormalities, and both acquire 2p gain and 5q deletion at sAML stage. The molecular mechanisms associated with leukemic progression in MPN patients are not clear. Our WES data showed TP53 alterations recurrently observed as mutations (missense and frameshift) and monoallelic loss. On the other hand, aCGH showed novel chromosome abnormalities (+2p and del5q) potentially associated with disease progression. The results reported here add valuable information to the still fragmented molecular basis of ET to sAML evolution. Further studies are necessary to identify minimal deleted/amplified region and genes relevant to sAML transformation.

Diagnosis of del(5q) MDS, 14 Years after JAK-2 Positive PV Appearance: Complete Remission of both Diseases with Lenalidomide Monotherapy

This is the report of the clinical case of a patient who presents the association of a JAK-2 positive chronic myeloproliferative neoplasia to a subsequent 5q- myelodysplastic syndrome, developed after about 14 years from the first diagnosis. Patient’s symptoms had rapidly worsened, and she became transfusion-dependent. Therapy with low-dose Lenalidomide quickly reduced the splenomegaly and completely brought white cells counts, haemoglobin, and platelets back to normal. After more than one year from the start, blood cell count is still normal. As far as we know, this is the first case of an effective treatment with Lenalidomide reported in this clinical setting.

Pathological interactions between hematopoietic stem cells and their niche revealed by mouse models of primary myelofibrosis

Primary myelofibrosis (PMF) belongs to the Philadelphia-negative myeloproliferative neoplasms and is a hematological disorder caused by abnormal function of the hematopoietic stem cells. The disease manifests itself with a plethora of alterations, including anemia, splenomegaly and extramedullary hematopoiesis. Its hallmarks are progressive marrow fibrosis and atypical megakaryocytic hyperplasia, two distinctive features used to clinically monitor disease progression. In an attempt to investigate the role of abnormal megakaryocytopoiesis in the pathogenesis of PMF, several transgenic mouse models have been generated. These models are based either on mutations that interfere with the extrinsic (thrombopoietin and its receptor, MPL) and intrinsic (the GATA1 transcription factor) control of normal megakaryocytopoiesis, or on known genetic lesions associated with the human disease. Here we provide an up-to-date review on the insights into the pathobiology of human PMF achieved by studying these animal models, with particular emphasis on results obtained with Gata1(low) mice.

Morphologic and cytogenetic differences between post-polycythemic myelofibrosis and primary myelofibrosis in fibrotic stage

Polycythemia vera and primary myelofibrosis share a propensity to progress toward a myelofibrotic late stage with overlapping clinical characteristics. Bone marrow features potentially useful for distinguishing the two entities have not been thoroughly investigated and, currently, clinical history is used for purposes of disease classification. This study describes in detail the morphologic features of 23 cases of post-polycythemic myelofibrosis and 15 cases of primary myelofibrosis with a similar degree of fibrosis, from two large medical centers. Cytogenetic results were available in 19 post-polycythemic myelofibrosis and in 13 primary myelofibrosis cases. JAK2 status and follow-up information was available in all cases. Cellularity was increased in both groups, but more so in post-polycythemic myelofibrosis than in primary myelofibrosis. In post-polycythemic myelofibrosis, most megakaryocytes retained polycythemia vera-like features including normally folded and/or hyperlobulated nuclei devoid of severe maturation defects; only in a few cases were rare tight clusters present. In primary myelofibrosis cases, megakaryocytes showed pronounced anomalies, including increased nuclear:cytoplasmic ratio, abnormal clumping of chromatin and frequent tight clustering. No differences in blast number (<1%) or in the myeloid:erythroid ratio were observed. Post-polycythemic myelofibrosis showed a higher degree of karyotypic alterations and higher percentage of cases with complex karyotype and/or two or more clones. Chromosome 1 defects were common in post-polycythemic myelofibrosis, whereas isolated del(20q) was the most common alteration in primary myelofibrosis. No survival differences were noted between the two groups. Post-polycythemic myelofibrosis cases retain a distinct megakaryocytic morphology that represents a useful clue for differential diagnosis. In addition, they more often display a complex karyotype than do primary myelofibrosis cases. These results suggest that myelofibrosis in polycythemia vera represents a form of progression characterized by profound genetic damage whereas in primary myelofibrosis it is an intrinsic part of the phenotypic manifestation of the disease, not necessarily associated with adverse cytogenetics.

Chromosome 5q deletion is extremely rare in patients with myelofibrosis

Chromosome 5q deletion can be found in rare cases of myelofibrosis (MF) but the incidence, clinical significance and response to therapies are not well studied. We retrospectively reviewed charts of 939 patients with MF and identified 8 patients [0.8%] who carried 5q deletion. Of the 8, seven had complex cytogenetic abnormalities and one had additional clone with different cytogenetic abnormality. All 8 had significant three-lineage pancytopenia. Three patients took lenalidomide and one (patient with 5q-clone) achieved long-lasting hematologic response. Two patients responded to JAK2 inhibitor therapy. MF patients with 5q deletion often have complex karyotype and poor outcome.

WHO-defined 'myelodysplastic syndrome with isolated del(5q)' in 88 consecutive patients: survival data, leukemic transformation rates and prevalence of JAK2, MPL and IDH mutations

The 2008 World Health Organization (WHO) criteria were used to identify 88 consecutive Mayo Clinic patients with ‘myelodysplastic syndrome with isolated del(5q)' (median age 74 years; 60 females). In all, 60 (68%) patients were followed up to the time of their death. Overall median survival was 66 months; leukemic transformation was documented in five (5.7%) cases. Multivariable analysis identified age ⩾70 years (P=0.01), transfusion need at diagnosis (P=0.04) and dysgranulopoiesis (P=0.02) as independent predictors of shortened survival; the presence of zero (low risk), one (intermediate risk) or ⩾2 (high risk) risk factors corresponded to median survivals of 102, 52 and 27 months, respectively. Janus kinase 2 (JAK2), thrombopoietin receptor (MPL), isocitrate dehydrogenase 1 (IDH1) and IDH2 mutational analysis was performed on archived bone marrows in 78 patients; JAK2V617F and MPLW515L mutations were shown in five (6.4%) and three (3.8%) patients, respectively, and did not seem to affect phenotype or prognosis. IDH mutations were not detected. Survival was not affected by serum ferritin and there were no instances of death directly related to iron overload. The current study is unique in its strict adherence to WHO criteria for selecting study patients and providing information on long-term survival, practical prognostic factors, baseline risk of leukemic transformation and the prevalence of JAK2, MPL and IDH mutations.