Myeloproliferative neoplasms (MPNs) are associated with the fewest number of mutations among known cancers. The mutations propelling these malignancies are phenotypic drivers providing an important ...implement for diagnosis, treatment response monitoring, and gaining insight into the disease biology. The phenotypic drivers of Philadelphia chromosome negative MPN include mutations in JAK2, CALR, and MPL. The most prevalent driver mutation JAK2V617F can cause disease entities such as essential thrombocythemia (ET) and polycythemia vera (PV). The divergent development is considered to be influenced by the acquisition order of the phenotypic driver mutation relative to other MPN-related mutations such as TET2 and DNMT3A. Advances in molecular biology revealed emergence of clonal hematopoiesis (CH) to be inevitable with aging and associated with risk factors beyond the development of blood cancers. In addition to its well-established role in thrombosis, the JAK2V617F mutation is particularly connected to the risk of developing cardiovascular disease (CVD), a pertinent issue, as deep molecular screening has revealed the prevalence of the mutation to be much higher in the background population than previously anticipated. Recent findings suggest a profound under-diagnosis of MPNs, and considering the impact of CVD on society, this calls for early detection of phenotypic driver mutations and clinical intervention.
Patients with accelerated or blast phase myeloproliferative neoplasms have a dismal prognosis. The report by de Castro et al. provides important information on the rationale and prospect for a novel ...therapeutic approach combining interferon-alpha2 with 5-azacytidine and a JAK1-2 inhibitor (ruxolitinib) to be explored in well-designed clinical trials. Commentary on: Castro et al. Ratio of stemness to interferon signalling as a biomarker and therapeutic target of myeloproliferative neoplasm progression to acute myeloid leukaemia. Br J Haematol 2024;204:206-220.
Peripheral T cell CXCR3 expression has been found uniquely lower in patients having neovascular age-related macular degeneration (nAMD) than in healthy individuals. The CXCR3-axis has been shown to ...have angiostatic and antifibrotic properties. We have recently investigated systemic markers in patients with myeloproliferative neoplasms (MPNs) because of their higher prevalence of AMD, and we have observed higher systemic chronic low-grade inflammation and immunosenescence signs in MPNs with drusen (MPNd) compared to those with normal retinas (MPNn). The MPNs evolve in a biological continuum from early cancer-stages (essential thrombocytosis, polycythemia vera) to the advanced myelofibrosis stage. Especially myelofibrosis is characterized by bone marrow angiogenesis and fibrosis, similarly to retinal observations in nAMD. We speculate if we can find lower CXCR3 expression in MPNs, particularly myelofibrosis and if differences are seen between MPNd and MPNn. We also wanted to compare expression in nAMD and intermediate (i)AMD.
Patients in this cross-sectional study were 29 nAMD, 28 iAMD, 35 MPNd, and 27 MPNn. We performed flowcytometry on blood to measure CXCR3 expression.
CD8+CXCR3 expression in nAMD was 6,1%, significantly lower than in iAMD 16%, MPNd 11%, MPNn 12% (p-values<0.05). Similar results were seen for CD4+CXCR3 expression. We also found CXCR3 expression decreasing over the MPN-continuum. For instance, in myelofibrosis, intermediate monocytes expression was 6.2%, significantly lower than 18% in ET and 18% in PV (p-values<0.05).
We find CXCR3 downregulation on T-cells and some monocyte subset in nAMD compared to iAMD, MPNd, and MPNn, in line with previous nAMD studies. We also find CXCR3 downregulation in most monocyte subsets over the MPN continuum. Systemic leukocyte CXCR3 expression could both be involved in changes seen in the retina and the bone marrow. Further understanding the CXCR3-axis in AMD and MPNs may elucidate underlying pathogenic mechanisms and reveal new targets for treatment.
Immune responses play a key role in the pathogenesis and progression of myeloproliferative neoplasms (MPN) and age-related macular degeneration (AMD). Recent studies suggested using MPNs as a "Human ...Inflammation Model" of drusen development and previous results showed interleukin-4 (IL-4) dysregulation in MPN and AMD. IL-4, IL-13 and IL-33 are all cytokines involved in the type 2 inflammatory response. This study investigated the cytokine levels of IL-4, IL-13 and IL-33 in serum of MPN and AMD patients. This cross-sectional study included 35 patients with MPN with drusen (MPNd) and 27 with MPN and normal retinas (MPNn), 28 patients with intermediate AMD (iAMD) and 29 with neovascular AMD (nAMD). With immunoassays, we quantified and compared levels of IL-4, IL-13 and IL-33 in serum between the groups. The study was conducted at Zealand University Hospital, Roskilde, Denmark, between July 2018 and November 2020. The serum levels of IL-4 were significantly higher in the MPNd group than in the MPNn group (p = 0.003). In regard to IL-33, the difference between MPNd and MPNn was not significant (p = 0.069), however, when subdivided into subgroups, a significant difference was found between polycythemia vera patients with drusen and those without drusen (p = 0.005). We found no IL-13 difference between the MPNd and MPNn groups. Our data didn't show any significant IL-4 or IL-13 serum level difference between the MPNd and iAMD groups but in regard to IL-33, data recorded a significant serum level difference between the two groups. There was no statistically significant difference between the MPNn, iAMD and nAMD groups in levels of IL-4, IL-13 and IL-33. These findings suggested that the serum levels of IL-4 and IL-33 might play a role in drusen development in MPN patients. The results might represent the type 2 inflammatory arm of the disease. The findings support the association between chronic inflammation and drusen.
The chronic Philadelphia-negative myeloproliferative neoplasms (MPNs) are acquired stem cell neoplasms which ultimately may transform to acute myelogenous leukemia. Most recently, chronic ...inflammation has been described as an important factor for the development and progression of MPNs in the biological continuum from early cancer stage to the advanced myelofibrosis stage, the MPNs being described as "A Human Inflammation Model for Cancer Development". This novel concept has been built upon clinical, experimental, genomic, immunological and not least epidemiological studies. Only a few studies have described the development of MPNs by mathematical models, and none have addressed the role of inflammation for clonal evolution and disease progression. Herein, we aim at using mathematical modelling to substantiate the concept of chronic inflammation as an important trigger and driver of MPNs.The basics of the model describe the proliferation from stem cells to mature cells including mutations of healthy stem cells to become malignant stem cells. We include a simple inflammatory coupling coping with cell death and affecting the basic model beneath. First, we describe the system without feedbacks or regulatory interactions. Next, we introduce inflammatory feedback into the system. Finally, we include other feedbacks and regulatory interactions forming the inflammatory-MPN model. Using mathematical modeling, we add further proof to the concept that chronic inflammation may be both a trigger of clonal evolution and an important driving force for MPN disease progression. Our findings support intervention at the earliest stage of cancer development to target the malignant clone and dampen concomitant inflammation.
Abstract
The hematopoietic stem cell (HSC) niche is a crucial driver of regeneration and malignancy. Its interaction with hematopoietic and malignant stem cells is highly complex and direct ...experimental observations are challenging. We here develop a mathematical model which helps relate processes in the niche to measurable changes of stem and non-stem cell counts. HSC attached to the niche are assumed to be quiescent. After detachment HSC become activated and divide or differentiate. To maintain their stemness, the progeny originating from division must reattach to the niche. We use mouse data from literature to parametrize the model. By combining mathematical analysis and computer simulations, we systematically investigate the impact of stem cell proliferation, differentiation, niche attachment, and detachment on clinically relevant scenarios. These include bone marrow transplantation, clonal competition, and eradication of malignant cells. According to our model, sampling of blood or bulk marrow provides only limited information about cellular interactions in the niche and the clonal composition of the stem cell population. Furthermore, we investigate how interference with processes in the stem cell niche could help to increase the effect of low-dose chemotherapy or to improve the homing of genetically engineered cells.
Graphical Abstract
Processes in the hematopoietic stem cell (HSC) niche impact clonal fitness. Increased self-renewal or attachment rates confer a competitive advantage to a mutated clone, increased differentiation implies a disadvantage. Detachment rates have no impact. Depending on these processes the mutated cell burden in the stem cell niche can be higher or lower compared to progenitors and mature cells.
Meta‐analyses and Mendelian randomization (MR) may clarify the associations of smoking, blood cells and myeloproliferative neoplasms (MPN). We investigated the association of smoking with blood cells ...in the Danish General Suburban Population Study (GESUS, n = 11 083), by meta‐analyses (including GESUS) of 92 studies (n = 531 741) and MR of smoking variant CHRNA3 (rs1051730A) in UK Biobank, and with MPN in a meta‐analysis of six studies (n (total/cases):1 425 529/2187), totalling 2 307 745 participants. In the meta‐analysis the random‐effects standardized mean difference (SMD) in current smokers versus non‐smokers was 0·82 (0·75–0·89, P = 2·0 * 10−108) for leukocytes, 0·09 (−0·02 to 0·21, P = 0·12) for erythrocytes, 0·53 (0·42–0·64, P = 8·0 * 10−22) for haematocrit, 0·42 (0·34–0·51, P = 7·1 * 10−21) for haemoglobin, 0·19 (0·08–0·31, P = 1·2 * 10−3) for mean corpuscular haemoglobin (MCH), 0·29 (0·19–0·39, P = 1·6 * 10−8) for mean corpuscular volume (MCV), and 0·04 (−0·04 to 0·13, P = 0·34) for platelets with trends for ever/ex‐/current smokers, light/heavy smokers and female/male smokers. Analyses presented high heterogeneity but low publication bias. Per allele in CHRNA3, cigarettes per day in current smokers was associated with increased blood cell counts (leukocytes, neutrophils), MCH, red cell distribution width (RDW) and MCV. The pooled fixed‐effects odds ratio for MPN was 1·44 95% confidence interval (CI): 1·33–1·56; P = 1·8 * 10−19; I2 = 0% in current smokers, 1·29 (1·15–1·44; P = 8·0 * 10−6; I2 = 0%) in ex‐smokers, 1·49 (1·26–1·77; P = 4·4 * 10−6; I2 = 0%) in light smokers and 2·04 (1·74–2·39, P = 2·3 * 10−18; I2 = 51%) in heavy smokers compared with non‐smokers. Smoking is observationally and genetically associated with increased leukocyte counts and red blood cell indices (MCH, MCV, RDW) and observationally with risk of MPN in current and ex‐smokers versus non/never‐smokers.
The Philadelphia-negative chronic myeloproliferative neoplasms - essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF) (MPNs) - have recently been shown to be associated with ...chronic inflammation, oxidative stress and accumulation of reactive oxygen species (ROS). Using whole blood transcriptional profiling, we report that several oxidative stress and anti-oxidative stress genes are significantly deregulated in MPNs. Among the twenty most up- and downregulated genes, ATOX1, DEFB122, GPX8, PRDX2, PRDX6, PTGS1, and SEPP1 were progressively upregulated from ET over PV to PMF, whereas AKR1B1, CYBA, SIRT2, TTN, and UCP2 were progressively downregulated in ET, PV and PMF (all FDR <0.05). The gene Nrf2, encoding the transcription factor nuclear factor erythroid 2-related factor 2 (NFE2L2 or Nrf2) was significantly downregulated in all MPNs. Nrf2 has a key role in the regulation of the oxidative stress response and modulates both migration and retention of hematopoietic stem cells (HSCs) in their niche. The patogenetic importance of Nrf2 depletion in the context of expansion of the hematopoietic progenitor pool in MPNs is discussed with particular focus upon the implications of concomitant downregulation of Nrf2 and CXCR4 for stem cell mobilization.
Discovery of somatic mutations in the calreticulin gene (CALR) has identified a subgroup of Philadelphia-negative chronic myeloproliferative neoplasms (MPN) with separate haematological ...characteristics and prognosis. CALR mutations serve as novel markers both of diagnostic value and as targets for monitoring molecular responses during therapy. Interferon-α (IFN) selectively targets the malignant clone in a subset of MPN patients and can induce both haematological and molecular remissions in CALR mutated essential thrombocythemia (ET) patients. We investigated the response to IFN in a cohort of 21 CALR mutated MPN patients including ET, prefibrotic primary myelofibrosis (pre-PMF), and primary myelofibrosis (PMF) with a median follow-up of 31 months. For evaluation of a molecular response, we developed highly sensitive quantitative PCR (qPCR) assays for monitoring the mutant allele burden of the two most prevalent CALR mutations (type 1 and type 2). Thirteen patients (62%) experienced a decrease in the mutant allele burden with a median decline of 29% from baseline. However, only four patients, including patients with ET, pre-PMF, and PMF diagnosis, achieved molecular responder (MR) status with >50% reduction in mutant allele burden according to European LeukemiaNet (ELN) guidelines. MR patients displayed significant differences in the dynamics of the CALR mutant load with regard to time to response and dynamics in mutant allele burden after discontinuation of IFN treatment. Furthermore, we highlight the prognostic value of the CALR mutant allele burden by showing a close association with leucocyte- and platelet counts, hemoglobin concentration, in addition to plasma lactate dehydrogenase (LDH) irrespective of molecular response and treatment status.
Summary
The effects of smoking on the molecular response (MR) and overall survival (OS) in patients with chronic myeloproliferative neoplasms (MPNs) have not been investigated before. We analysed a ...historical cohort of 498 consecutive patients diagnosed with MPNs. Moreover, we analysed a subgroup of 270 consecutive patients with MPNs with > 1 measurement of the JAK2V617F variant allele frequency. The data were analysed using Kaplan–Meier plots and Cox regression analysis, along with linear regression models. In all patients, the rate of MR was significantly higher in never‐smokers compared with current smokers in the univariate model (HR, 1·9; 95% CI, 1·1–3·3; P = 0·033) and the multivariate model (HR, 1·9; 95% CI, 1·1–3·5; P = 0·029). Similar findings were observed with different cut‐off values for a partial MR. A subgroup analysis including only interferon‐α2‐treated patients showed similar results. In multivariate analyses, the OS was significantly better for never‐smokers (HR, 0·46; 95% CI, 0·29–0·75; P = 0·002) than current smokers. The differences were more pronounced in the pegylated interferon‐α2‐treated patients. However, no significant interaction of interferon‐α2 treatment was observed. In conclusion, we found that tobacco smoking reduced the rate of MR and OS in patients with MPNs. Cessation of smoking should be encouraged.
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