CALR mutation

There is a possibility that human segregated-nucleus-containing atypical monocytes exist in the bone marrow of primary myelofibrosis patients and might be related to marrow fibrosis.

The JAK1/2 inhibitor, ruxolitinib, which increased the uSTAT5:pSTAT5 ratio, had similar effects on murine HSC function: it constrained HSC differentiation and proliferation, promoted HSC maintenance and upregulated transcriptional programs associated with stemness...Our results therefore reveal a previously unrecognized interplay between pSTAT5 and uSTAT5 in the control of HSC function and highlight JAK inhibition as a potential strategy for enhancing HSC function during ex vivo culture. Increased levels of uSTAT5 may also contribute to the failure of JAK inhibitors to eradicate myeloproliferative neoplasms.

In conclusion, the HLA-I genotype differentially restricts JAK2 V617F and CALRmut-driven oncogenesis potentially explaining the mutual exclusivity of the two mutations and differences in their presentation latency. These findings have practical implications for the development of neoantigen-based vaccines in MPNs.

In order to potentially increase clinical benefit for patients with MF, several novel agents are being partnered with ruxolitinib (RUX) with the ongoing hypothesis to augment greater measures of MF disease modification. The novel agents are either 'added-on' to RUX or as a combo in JAKi naïve patients. Also, the mutant-targeting era of therapies is now beginning with novel CALR-mutated, novel JAK2 V617F mutation-specific and type II JAK2i in the initial stages of drug development, representing a new approach to treatment.

It was revealed that the accumulation of G2/M-CALR-mutated cells indicates that oxidative stress-induced DNA damage is difficult to repair. Taken together, this study contributes to a deeper understanding of the specific molecular mechanisms underlying CALR-mutated MPNs.

Our results suggest that impaired tPA-mediated fibrinolysis represents an important pro-thrombotic mechanism in MPN patients that requires confirmation on larger studies.

INCA033989 reduced the pathogenic self-renewal of mutCALR-positive disease-initiating cells in both primary and secondary transplantations, illustrating its disease-modifying potential. In summary, we describe a novel mutCALR-targeted therapy for MPNs, a monoclonal antibody that selectively inhibits the oncogenic function of MPN cells without interfering with normal hematopoiesis.

MPN patients, especially those with PMF, have a significant granulocyte developmental overmaturation phenotype. CD10+ granulocytes may be involved in the prognosis of PMF patients.

Our data suggest that secondary AML arising from MPNs is a genetically distinct entity compared to de novoAML, with a higher incidence of mutations in high-risk genes such as TP53, a high rate of relapse/refractorinessand poor prognosis with current therapeutic strategies. NGS determination of somatic mutations could identifyhigh-risk-progression patients, and monitoring these mutations could be useful, along with other clinical data,to anticipate progression.

Our data on the driver gene mutational profile of BCR: ABL1 negative MPN is one of the largest patient cohorts. The prevalence and clinicopathological features corroborate with that of other Asian studies.

The use of drugs targeting the activation or blockade of this target in the analyzed cell lines did not result in changes in cell viability. However, RXRA might be relevant in the disease, pointing to the need for future research testing retinoids and other drugs targeting RXRα for the treatment of ET patients.

mTOR inhibition also reduces colony formation and differentiation of CD34+ cells from MPN patients but not healthy donors. Together, these findings indicate low surface MPL as a biomarker of mutant CRT-mediated MPN and induced degradation of CRTDel52 and MPL as an avenue for therapeutic intervention.

The presence of BCR::ABL1 translocation with a coexisting CALR mutation is even more uncommon. Herein, starting from a routinely diagnosed case of CALR-mutated primary myelofibrosis subsequently acquiring BCR::ABL1 translocation, we performed a comprehensive review of the literature, discussing the clinicopathologic and molecular features, as well as the outcome and treatment of cases with BCR::ABL1 and CALR co-occurrence.

This report highlights the impact of JAK2 and CALR mutations on Ca2+ flux (store depletion and SOCE) in response to stimulation with EPO and TPO. The study shows that the JAK2-V617F mutation strongly alters the regulatory mechanism of EpoR/JAK2-dependent intracellular calcium balance, affecting baseline calcium levels, EPO-induced calcium entry, and PLCγ-1 signaling pathways. Our results reveal an important role of calcium flux in the homeostasis of JAK2-V617F positive cells.

P1, N=10, Recruiting, Marina Kremyanskaya | Trial completion date: Jan 2025 --> Mar 2026 | Trial primary completion date: Jan 2024 --> Mar 2026

JAK2V617F was strongly associated with thrombosis and worse TFS. Hydroxyurea was the most preferred cytoreductive agent for patients with high thrombosis risk.

There are differences in blood cell count and coagulation status among ET patients with different driver gene mutations. Among ET patients, JAK2 mutation is most common. Compared with CALR group, the thrombotic rate, WBC and Fg significantly increase in JAK2 group, while PLT decrease. Compared with triple-negative group, the incidence of splenomegaly and HCT significantly increase. Compared with CALR group, Fg significantly increases but APTT decreases in triple-negative group.

A low allele burden (i.e., <20%) of the CALR driver mutation is found in 10.8% of CALR-mutated MPNs, mostly in essential thrombocythemia, and correlates with a milder phenotype and a more indolent evolution compared to patients with an allele burden ≥20%.

She was started on aspirin alone as she was less than 60 years old and had no history of thrombotic events...CONCLUSIONS We propose that in patients with a low JAK2 V617 allele variant, testing for other driver mutations should be performed. In our patient, JAK2 mutation could be clonal hematopoiesis of indeterminate potential; therefore, the dominant mutation (CALR) would determine the disease phenotype.

Starting from the presentation of two additional cases from our routine daily practice, we focus mainly on clinical, laboratory, and bone marrow histological findings, which may represent useful clues of BCR::ABL1 and JAK2 co-occurrence. The interaction between JAK2 and BCR::ABL1 clones during the disease course as well as therapy and outcome are presented.

No abstract available

By analyzing peripheral blood for the mutation JAK2 p.V617F, an important cause of these rare thrombotic events can be identified. The development of a diagnostic workup with next-generation ultradeep sequencing for the analysis of the JAK2 p.V617F mutation and further mutations has the potential to better understand the etiology of abdominal venous thromboses in individual patients in regional clinical care, as abdominal venous thromboses are diagnosed by various medical disciplines.

Aspirin therapy appeared to mitigate both arterial (HR 0.4) and venous (HR 0.4) thrombosis risk. HR-based risk models delineated patients with median survivals ranging from 10 years to not reached and 20-year leukemia/myelofibrosis incidences from 3%/21% to 12.8%/49%. The current study provides both novel and confirmatory observations of essential thrombocythemia.

Cytoreductive therapy appeared to mitigate both venous (HR 0.3; p = 0.01) and arterial thrombosis (HR 4; p = 0.04); there was a trend for aspirin in preventing arterial thrombosis recurrence. The current study provides real-world observations in essential thrombocythemia, representing a valid source document for interpreting current literature and planning future studies.

Among 281 patients with essential thrombocythemia and calreticulin mutation, we found a variant allele frequency of >60% to be associated with significantly shortened myelofibrosis-free survival, mostly apparent with CALR type-1 and CALR type-indeterminate mutations.

We further demonstrated that JAK2N533S, as a noncanonical JAK2 exon12 mutation, is a germline mutation that may not exert an effect on cell proliferation and protein function. These results and the present body of available data imply that certain noncanonical JAK2 mutations are not gain-of-function mutations leading to the development of myeloproliferative neoplasms.

Regarding the hematological results for the mutations, significant differences were found in the hemoglobin level, hematocrit level, and platelet count among the three neoplasms. Thus, this study demonstrates the importance of the molecular characterization of the JAK2, CALR and MPL mutations in Colombian patients (the genetic context of which remains unclear in the abovementioned neoplasms) to achieve an accurate diagnosis, a good prognosis, adequate management, and patient survival.

P1, N=18, Completed, City of Hope Medical Center | Active, not recruiting --> Completed

We found no correlation between hemorrhagic risk and gender or mutational status. Results of our study highlight the validity of IPSET-t score in predicting individual hemorrhagic risk among ET patients, suggesting a possible role of IPSET-t scoring system as a global evaluator for vascular events in ET patients.

Patients receiving busulfan-containing regimens achieved a 5-year OS rate of 71%...Comparative analysis between CALR- and JAK2-mutated MF patients adjusting for confounding factors revealed better OS, lower NRM, lower relapse, and improved graft-versus-host disease-free and relapse-free survival (GRFS) in CALR-mutated patients. These findings confirm the improved prognosis associated with CALR mutation in allo-HCT and support molecular profiling in prognostic scoring systems to predict OS after transplantation in MF.

Although great progress has been made in the understanding of MPN clonal hematopoiesis and its evolution with the development of next-generation sequencing, there are still many limitations. In this study, we mainly discuss gene mutations of MPN and their influences on the thrombosis, leukemia and fibrosis transformation, and the influencing factors of clonal evolution, aiming to summarize the influence of clonal hematopoiesis and its evolution on the complications, prognosis and survival of MPN.

The limitations of this study are its small size, single community investigator, retrospective clinical nature, and the lack of gene sequencing and other molecular studies in most if not all of the patients. This observation was noted over three years in a single community practice which strongly implies that combined occurrence may be more common than recognized and suggests that further investigation is warranted.

ConclusionsRed cells distribution width may represent a good integrative measure of several disease processes and also has prognostic significance at the time of MF diagnosis and during RUX treatment. Even though our preliminary observations are limited by the small number of patients and need to be further confirmed by larger studies, we can speculate that RDW may help in the rapid detection of MF patients with a poor prognosis, which can only partially be improved from currently available targeted therapies with JAK inhibitors.

Von Willebrand antigen (VWF: Ag) (normal: 60-160 U/dL), von Willebrand factor (VWF) activity (VWF: GPIbM) (normal: 60-160 U/dL) and closure time with the platelet function analyzer (PFA-200) (pathological: collagen-Epinephrine channel > 200 seconds; collagen-ADP channel > 140 seconds) were assessed...ASA resistance was associated with a higher platelet count and higher VWF: GPIbM. 50% of the patients with increased VWF: GPIbM (>160 U/dL) had resistance to ASA, showing VWF: GPIbM as an independent variable in the multivariate analysis.

Among 123 patients with MPN,57 patients were diagnosed with ET with a median age of 62 years (range, 20-86), 17 patients were diagnosed with PV with a median age of 53 years (range, 19-70), 49 patients were diagnosed with PMF with a median age of 63 years (range, 26-81). 55 patients had varying degrees of splenomegaly, of which 14 (24. 6%) patients with ET, 32 (65.

Prior to ropeginterferon-alfa, the participants were managed with therapeutic phlebotomies, or cytoreduced with either hydroxyurea, pegylated interferon-alpha 2a ( Pegasys), JAK2 inhibitors, or were newly diagnosed and previously untreated. Ropeginterferon-alfa is effective in PV and ET, however, the dose that achieves CHR is highly individualized, necessitating an incremental titration approach. The patients already in CHR from prior therapy needed relatively lower doses of ropeginterferon-alfa to maintain CHR. Clinical trials are ongoing with an alternate accelerated dosing scheme and results are awaited.

5%; 25/55) and hydroxycarbamide (43...8%) receiving warfarin rather than a DOAC...Whilst traditionally younger patients are considered to have ‘low risk’ disease, this real-world study highlights a significant thrombosis rate of ~ 20% which may have associated morbidity considering the relatively longer duration of the disease course and need for cytoreductive therapy. Specific AYA MPN directed risk stratification and therapeutic algorithms are required to inform holistic and age-appropriate patient management.

Given the significant likelihood of OSA in patients with PV and ET (as based on STOP-BANG scores of 3 or more), there is need to evaluate and treat for OSA. Preliminary results show abnormalities in inflammatory markers with reductions in C-reactive protein and erythropoietin levels following CPAP therapy even though mixed results were noted in inflammatory and HIF-target gene transcripts, and markers of iron turnover. Larger studies and longer follow-up are required to understand the impact of OSA on not only the thrombotic and inflammatory milieu in patients with MPNs, but also the benefit of treating on prevention of disease progression and thrombotic manifestations common in MPNs.

Treatment was ruxolitinib and hydroxyurea...He started dasatinib and decitabine, which resulted in a drop from 28...However, hyperuricemia and renal failure led to a change in regimen and the patient was started on asciminib and ropeginterferon alfa-2b-njft in January 2022...He received cladribine and cytarabine, but was found to have leukemic infiltration of the spinal cord five months later...However, he always maintained a high CALR burden. This patient's mutational profile and disease course argue for the importance of early testing for CALR and BCR-ABL in addition to JAK2 and MPL in the setting of an MPN and for further research into the underlying causes of these overlap conditions.