JAK2 Exon Research Articles

High-resolution melting assay for rapid, simultaneous detection of JAK2, MPL and CALR variants

AimsIdentification of recurrent genetic alterations in JAK2, MPL and CALR remains crucial in the diagnosis of Philadelphia-negative myeloproliferative neoplasms (MPNs). Current laboratory testing algorithms may entail batching and/or sequential testing,...

Evaluation of Philadelphia-negative myeloproliferative neoplasms in Erbil Iraq; analysis of JAK 2, CALR, and MPL mutations

Introduction: The prevalence of Janus kinase 2 V617F, Jak 2-Exon12, calreticulin (CALR) gene mutations and myeloproliferative leukemia mutations in myeloproliferative neoplasms (MPNs) without BCR-ABL1 gene fusion rearrangement in Iraq remains unknown due to inadequate data. Objectives: The aim of this study was to ascertain the prevalence of these mutations and assess the clinical characteristics of polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) in Erbil, Iraq. Patients and Methods: In this cross-sectional study, 80 patients were evaluated for the presence of JAK 2 V617, CALR, and MPL mutations. Specific primers were utilized to amplify MPNs-associated mutations (JAK 2 V617F, Jak 2 -Exon12, CALR, and MPL) using DNA extracted from whole blood. Results: The presence of the JAK 2 V617F mutation was identified in 96% of patients diagnosed with PV and 35% of patients diagnosed with ET. Additionally, JAK 2 exon 12 was detected in 4% of PV patients. CALR mutation was identified in 65% of ET patients. No detection of MPL mutation was observed. A higher prevalence of the CALR mutation was observed in younger age groups, whereas the JAK 2 V617F mutation was predominantly found in older age groups. Conclusion: The incorporation of genetic tests for JAK 2 V617F, JAK 2 exon 12, MPL exon 10, and CALR exon 9 significantly improves the diagnostic effectiveness for BCR ABL1-gene fusion negative MPNs.

The assessment of health-related quality of life in patients with polycythemia vera.

Previous studies have shown that patients with polycythemia vera (PV) have poor quality of life (QoL). Similarly, it has been shown that survival is influenced by QoL. We aimed to evaluate QoL in 88 Turkish patients with PV. This cross-sectional study included cases diagnosed with PV between January 1995 and August 2019 who attended follow-up studies in the hematology department of a tertiary hospital in Türkiye between August 2019 and July 2020. Beginning in August 2019, subjects who approved study participation applied the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) questionnaire during their routine follow-up-given that they met inclusion/exclusion criteria. Individuals with comorbidities or factors influencing QoL and those with secondary PV-related conditions were excluded. Recorded data included age, sex, history of bleeding, thrombosis, erythrocytosis, leukocytosis, thrombocytosis, obesity or splenomegaly, and cytogenetic mutation profiles such as JAK2, BCR and MPL. We also assessed whether they needed phlebotomy or erythrocyte suspensions. Data concerning comorbidities and medication use were obtained from medical records. The median age of patients was 52 (44-61) years. The majority of participants were male (67.05%). Global health status score was 75 (66.67-83.33). PV patients who had required phlebotomy demonstrated higher social functioning scores (P = .004) and lower scores for loss of appetite (P = .013) and financial difficulties (P = .020) than patients without phlebotomy. PV patients who had suffered from leukocytosis demonstrated lower physical functioning scores compared to those without leukocytosis (P = .001). Patients without JAK2 exon 14 mutations had better physical (P = .016) and cognitive functioning scores (P = .048). It was found that PV patients with splenomegaly demonstrated lower physical functioning (P = .019) and higher appetite loss scores (P = .005) than those without splenomegaly. Higher leucocyte counts were associated with decreased physical functioning and greater fatigue. In conclusion, we demonstrated deterioration of physical and emotional QoL in patients diagnosed with PV. Patients with PV require individualized, patient-specific and integrated approaches in order to minimize symptoms, improve QoL, and increase survival.

A Novel JAK2 Fusion in T-Cell Prolymphocytic Leukemia.

T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive mature T-cell malignancy characterized by marked lymphocytosis, B symptoms, lymphadenopathy, and hepatosplenomegaly. There is no standard treatment approach, and in the absence of an allogeneic transplant, the prognosis remains poor. The disease-defining cytogenetic abnormality in T-PLL is the juxtaposition of the TCL1-family oncogene to the TCR gene enhancer locus primarily due to an inversion of chromosome 14, that is, inv(14). The application of next-generation sequencing technologies led to the discovery of highly recurrent gain-of-function mutations in JAK1/3 and STAT5B in over 70% of T-PLL providing opportunities for therapeutic intervention using small molecule inhibitors. Additional genetic mechanisms that may contribute to the pathogenesis of T-PLL remain unknown. Herein we describe the identification of a novel gene fusion SMCHD1::JAK2 resulting from a translocation between chromosome 9 and 18 involving SMCHD1 exon 45 and JAK2 exon 14 (t(9;18)(p24.1;p11.32)(chr9:g.5080171::chr18:g.2793269)), a previously undescribed genetic event in a patient with T-PLL harboring the key disease defining inv(14) resulting in rearrangement of TCL1 and TRA/D. In this manuscript, we describe the clinical and genetic features of the patient's disease course over a 25-month post-treatment duration using ruxolitinib and duvelisib.

ADAMTS13, von Willebrand Factor, Platelet Microparticles, Factor VIII, and Impact of Somatic Mutations in the Pathogenesis of Splanchnic Vein Thrombosis Associated with BCR-ABL-Negative Myeloproliferative Neoplasms.

Myeloproliferative neoplasms (MPNs) are often associated with splanchnic vein thrombosis (SVT). Not all the factors involved in the thrombotic tendency are currently known. This study aims to evaluate a possible association between ADAMTS13, von Willebrand factor (VWF), platelet microvesicles (MV), and factor VIII activity (FVIII:C) with thrombotic events in MPN patients. In total, 36 consecutive MPN patients with SVT were enrolled. The MPNs were diagnosed based on clinical characteristics and one or more gene mutations among JAK-2, CALR, and MPL. As controls, 50 randomly selected patients with MPN without thrombosis, 50 patients with deep vein thrombosis without MPNs, and 50 healthy blood donors were evaluated. Complete blood count, ADAMTS13, VWF, MV, and FVIII:C in plasma were measured in all the subjects. The JAK-2 mutation was found in 94% of the patients with SVT, but none were triple-negative for genetic mutations (JAK2 V617F, CALR, MPL, and exon 12). Compared to the normal subjects, in all the MPN patients (with or without SVT), the levels of ADAMTS13 were found to be significantly lower (p < 0.001) and the MV concentrations were significantly higher (p < 0.001). Among the MPN patients, the VWF and FVIII:C levels were significantly higher in the patients with SVT than those without thrombosis (p = 0.007 and p = 0.04, respectively). Splenomegaly was present in 78% of MPN patients with SVT and in 30% of those without SVT (p < 0.001). The ADAMTS13/VWF ratio was reduced in all the patients, but not in the healthy blood donors (p < 0.001). The significant increase in circulating MV, VWF, and FVIII:C in the MPN patients and in the patients with thrombosis supports the role of endothelium damage in promoting thrombotic events. In particular, a significant increase in VWF and FVIII:C levels was found in the MPN patients with SVT.

Sensitivity evaluation of methods for screening JAK2 exon 12 mutations based on heteroduplex and HRM analysis

Background. According to WHO guidelines, one of the criteria for diagnosis of polycythemia vera is the presence of somatic mutations in exon 12 of the JAK2 gene, but to date there is no universally accepted simple method to analyze these mutations. We have previously proposed two methods for screening such mutations based on heteroduplex and HRM (High Resolution Melt) assays, which are relatively cheap and fast compared to sequencing.Aim. To analyze the sensitivity of these screening methods.Materials and methods. The study used cloned DNA samples from 6 patients with various mutations in exon 12 of the JAK2 gene that we had previously identified, as well as a clone of the corresponding wild-type DNA segment. Dilution of the cloned mutant samples with wild-type clones was performed to obtain samples with different levels of allele burden: 100, 50, 25, 12.5, 6.25, 3.13, 1.56 and 0.78 %. Heteroduplex analysis followed by PAGE (polyacrylamide gel) and HRM analysis was then performed with the diluted samples.Results. The sensitivity threshold of the heteroduplex analysis was found to be between 3.13–6.25 % allele burdens depending on the specific mutation, the sensitivity threshold of the HRM assay was 6.25–12.5 % similarly.Conclusion. Our proposed methods of heteroduplex analysis followed by PAGE and HRM-analysis for the detection of polycythemia vera-specific mutations in exon 12 of the JAK2 gene allow increasing the efficiency of using different types of sequencing and can be used as simpler and less expensive methods of preliminary screening of these mutations.

Familial Polycythemia Associated with JAK2 Mutation Previously Known As Variant of Unknown Significance

Introduction Mutations in the Janus Kinase 2 gene (JAK2) are commonly encountered in patients with myeloproliferative neoplasms (MPN) including polycythemia vera (PV) and essential thrombocythemia. JAK2 mutations particularly V617F is associated with PV in 98% cases. Gain of function mutations in the JAK2 exon 12 are reported to be associated with isolated erythropoiesis. Atypical mutations in JAK2 including (c.3323A&amp;gt;G, p.N1108S) were reported in patients with MPN who tested negative for the established driver mutations including exon 14 JAK 2, exon 9 CALR and exon 10 MPL genes. Primary familial congenital polycythemia (PFCP) is a rare disease inherited in an autosomal dominant fashion caused by hypersensitivity of EPO receptor. In such cases, an EPO receptor mutation is only found in 12-15% of affected patients. Due to associated increased risk of thrombosis, bleeding, leukemic involvement and myelofibrosis in PV, bone marrow evaluation is essential in this patient population. In patients with polycythemia, the goals of treatment are to maintain appropriate level of hemoglobin/hematocrit and to reduce severity of symptoms. We present a family affected by polycythemia and leukocytosis associated with an atypical heterozygous variant of JAK2 [c.3323A&amp;gt;G (p.Asn1108Ser)] currently reported as benign or variant of unknown significance (VUS) in literature. Methods Case series, retrospective electronic medical record review with institutional board review exemption Results We report a case series of three Caucasian family members affected with JAK2 VUS mutation (mother and two sons). The proband is a 17-year-old male who presented to an outside facility at the age of 14 with complaints of fatigue, headache, and intense pruritis after hot showers. Initial workup was significant for marked erythrocytosis and reticulocytosis without evidence of abnormal cells on peripheral film. Bone marrow evaluation showed trilineage hematopoiesis with no morphological features of a myeloproliferative neoplasm. Genetic testing was negative for JAK2 V617F and exon 12 mutations. However, whole exome sequencing (WES) revealed a heterozygous mutation of JAK2 gene, c.3323A&amp;gt;G (p.Asn1108Ser). Additional investigation on proband's younger brother, who complained of similar symptoms, also revealed the same JAK2 variant. The proband's mother reported non-specific symptoms including headache, flushing, and occasional blurry vision that she previously attributed to hypertension. Her labs were significant for leukocytosis, monocytosis and thrombocytosis in the presence of normal red blood cell count and WES showed the same mutation. Bone marrow evaluation of the brother and the mother showed normal trilineage hematopoiesis and was negative for malignancy (Table 1). Proband's father is reportedly negative for the aforesaid mutation and is clinically asymptomatic. The proband and his brother are currently managed with phlebotomy every 3 to 4 weeks to maintain hematocrit below 45%, leading to improvement in symptoms. Cytoreductive therapies have been discussed but not initiated. Proband's mother is managed by an adult hematologist. Scheduled phlebotomies with close surveillance is recommended for clinical practice along with interval research sequencing. Conclusion Our case series reports a family with clinical features and laboratories suggestive of a familial form of polycythemia, WES detected the presence of an atypical JAK2 mutation: c.3323A&amp;gt;G, (p.Asn1108Ser). The phenotypical and clinical significance of this mutation has been considered non canonical per reports and classified as likely benign by reputable commercial genetic testing laboratories. However, other reports identify this JAK2 variant as having a significant increased prevalence in patients with MPNs and AML compared to the general population. It may result in a gain of function of the JAK2 protein and subsequent development of MPNs. Enrollment in research sequencing protocols is encouraged in such patients to closely follow the pathologic potential and spectrum of genetic variants rarely reported in literature. Additional research to determine the pathogenicity of this genetic variant is highly warranted.

Acquired Von Willebrand Syndrome, Epidemiology, Laboratory Findings and Molecular Alterations on Classic Myeloproliferative Neoplasms in Mexican Population

Introduction: Acquired von Willebrand syndrome (AvWS) has been associated with Philadelphia-negative chronic myeloproliferative neoplasms (MPN) since 1984. However, the epidemiology of these disorders is not precise and has been underestimated worldwide but prevalence of 10-20% has been described in other series. Determinations of the antigenic von Willebrand factor (VWF:Ag) and its activity (VWF:RCo) are only performed when patients present thrombocytosis over 1,000 x10 3/µL. Essential Thrombocythemia (ET) is the most commonly associated MPN, found in 5-30%. Some cases have been described in patients with polycythemia vera (PV) and primary myelofibrosis (PMF) who develop AvWS even with platelet counts below 1,000 x10 3/µL. The epidemiology of AvWS in MPN and its association between laboratory and molecular parameters among the Mexican population have not been described. Objectives - Describe the clinical, biochemical and molecular characteristics of patients who develop AvWS with the aim of establishing the difference between cut-off scores of platelets to suspect AvWS in Mexican patients. - Establish the association between mutations in JAK2, CALR and MPL, and the appearance of AvWS. Material and methods: Retrospective, descriptive, observational, and single-center analysis. Patients over 18 years of age with a diagnosis of MPN from the INCMNSZ were recruited. The mutational analysis in peripheral blood (PB) for JAK2, CALR and MPL was assessed, with at least one follow-up between 2012 and 2022, excluded whose medical record were incomplete. Information was consecutively collected from 184 patients with MPN diagnosis between 01/01/2000 to 05/31/2022. Thirty patients were identified as having AvWS with a VWF:RCo/VWF:Ag diagnostic ratio of &amp;lt; 0.7. The epidemiology, clinical, laboratory and mutational alterations of the patients who developed AvWS by was analyzed using descriptive statistics with SPSS. This study was approved by the institutional bioethics committee. Results: AvWS developed in 16.4% (n = 30) of patients with MPN with an annual incidence of 2.4 cases per year was identified. Most patients were women in 66% (n = 20), with a median age of 57 years (IQR 20-72 years). Of the thirty cases with AvWS, 46.7% (n =14) corresponded to PMF, 40% (n =12) to PV, and 13.3% to ET (n = 4). The most frequently found mutation was JAK2 exon 14 with 76.7%, followed by CALR in 13.3% and triple negatives in 10%, no patient presented MPL mutations. The global median of VWF:RCo/VWF:Ag was 0.47 [PV 0.47 (IQR 0.31-0.64), ET 0.53 (IQR 0.5-0.64) and PMF 0.48 (0.29-0.65)] (Figure 1) and the median of the VWF:Ag 118 U/dL with FVW:RCo of 44.6 UI/dL (Table 1). The median platelet count for patients with the JAK2 mutation was 987.9 x103/µL (IQR 218 - 2307 x10 3/µL), while those with CALR and triple negatives were 1,033 x10 3/µL (IQR 713 - 1339 x10 3/µL), and 1,325 x10 3/µL (IQR 760 - 2059 x10 3/µL), respectively. Regarding hemoglobin (Hb) and hematocrit (Hto) levels, patients with PV and JAK2 mutation with AvWS presented medians of 17.45 g/d and 54.4% respectively, highlighting that AvWS was generated in some patients with platelet counts below 1,000 x10 3/µL. At diagnosis, bleeding episodes occurred in 13.3%. Lastly, 96.7% of the patients were treated with hydroxyurea, which corrected cellular alterations and laboratory abnormalities found in AvWS. Conclusions: AvWS can be found in patients with platelet counts below 1,000 x10 3/µL, especially among those with PV with elevated Hb and Hct levels. This may deem it necessary to carry out diagnostic tests in patients with MPN and any degree of thrombocytosis. To our knowledge, this is the most comprehensive study among latin american patients that describes the coexistence of PMF and AvWS; even though the mechanism by which some PMF patients develop AvWS is not perfectly understood. In our study, patients with PMF presented AvWS more frequently; this is a contrasting result from other international reports where ET was most attributed. We attribute this finding to changes made to the WHO criteria between 2008 and 2016.

Importance of Diagnosing Polycythemia Vera (PV) Patients (pts) Whose Hematocrit (HCT)/Hemoglobin (HGB) Are Less Than the Who 2022 Stipulated Criteria

Introduction: HCT/HGB values stipulated by WHO in 2022 1* (and 2016) are required for distinguishing pts with PV from those with either essential thrombocythemia (ET), cellular phase primary myelofibrosis (MF), or JAK2-mutated clonal hematopoiesis. We verified WHO values have 100% specificity but only approximately 75% sensitivity 2. Thus, PV pts exist with values less than WHO criteria for HCT/HGB. Distinguishing these PV pts from ET, MF or CHIP is important since prognosis and management differs. No studies to date, however, have defined the frequency and characteristics of these specific PV pts. We therefore reviewed our cohort of PV pts to identify those whose HCT and HGB values were lower than WHO. We report their clinical, hematologic, and molecular findings and their survival to date. Methods : We queried our database of PV pts, extracting data as previously reported 3 for those with HCT/HGB values below WHO threshold at diagnosis (dx). These pts met PV diagnostic criteria by either marrow morphology, red cell mass (RCM), and/or erythropoietin (EPO) values. We recorded clinical, hematologic and JAK2 V617F variant allele frequency (VAF) findings, therapy, clinical course, MF free (MFS) and overall survival (OS). Results: Twelve of 470 (2.6%) pts had criteria of PV with HCT/HGB values below WHO. All were JAK2 V617F positive. 10 had quantitative values, with median VAF 18% (range 6.2-46.1%). Median age was 45 years. Mean erythrocyte values for males (N=4) and females (N=8) respectively were: HCT 47.5 and 42.4%, HGB 16.1 and 14.2 g/dL, RBC 5.18 and 5.13 x10 6 /uL, MCV 91.6 and 83.0 fL (Table 1). Cr-51 RCM was increased in 3. 11 pts had marrow biopsies showing varying degrees of hypercellularity and increased megakaryocytes with the characteristic morphologic changes described in PV. Patient 1 did not have Cornell review of marrow but otherwise had lab and clinical values consistent with PV (Table 2). 5 of 11 pts had an MF score of 0, 5 MF-1, and 1 MF-2. Stainable iron was absent in 5, present in 4, and not assessed in 2. Since low JAK2 VAF is associated with ET, in the 9 pts with VAF under 20%, or qualitative values only, the PV dx was made on marrow morphology and increased RCM, low EPO level, high RBC count or combinations thereof (Table 2). Seven pts were symptomatic at dx, including fatigue, headache, and generalized abdominal discomfort. Spleen was palpable at dx in 3 pts, 1, 8, and 9 cm below the left costal margin, respectively. The last two pts presented with splanchnic vein thrombosis. Another pt had a cerebrovascular accident at dx. Maintenance treatment was phlebotomy in 1, hydroxyurea 2, ruxolitinib 2, and rIFN 7. None of the pts progressed to MF; 1 pt died of colon cancer. Over a median follow up of 7 years, median MFS and OS have not been reached (100% MFS and 92% OS to date). Conclusion: A small number of PV pts present with HCT/HGB below WHO threshold; however, recognition is important because of their symptoms and risk of significant thrombosis. Our 12 pts were diagnosed with PV based on a combination of either marrow morphology, EPO level, and RCM. As isotopic RCM studies are difficult to obtain, RBC and marrow morphology becomes extremely important for correct dx. The presence of marrow iron stores in 4 pts is significant since most PV pts are iron deficient at dx 4. This suggests that the HCT/HGB values observed may represent “early” disease. The HCT/HGB values in the 2 splanchnic vein thrombosis pts with significant splenomegaly represent well-known splenic sequestration and increased plasma volume, masking true polycythemia. In these cases, marrow studies and EPO values are mandatory to distinguish PV from ET. This study emphasizes the appropriate use of RCM and should prompt development of alternative methods to measure blood volume. *2022 WHO PV diagnostic criteria 1: Major Criteria: 1. HGB &amp;gt; 16.5 g/dL (men) HGB &amp;gt; 16.0 g/dL (women) or HCT &amp;gt;49% (men) HCT &amp;gt; 48% (women) or increased red cell mass more than 25% above mean normal predicted value 2. BM biopsy showing hypercellularity for age with trilineage growth (panmyelosis) including prominent erythroid, granulocytic and megakaryotic proliferation with pleomorphic, mature megakaryocytes (differences in size) 3. Presence of JAK2 or JAK2 exon 12 mutation Minor criteria: subnormal serum erythropoietin level

Phase 2 Study to Assess the Safety and Efficacy of Bomedemstat (MK3543) in Combination with Ruxolitinib in Patients with Myelofibrosis

Background Approximately 50% of patients with myelofibrosis (MF) discontinue ruxolitinib after 3 years, mostly due to disease progression, suboptimal response or cytopenia. Outcome after ruxolitinib discontinuation is poor with a median overall survival (OS) of approximately 14 months. Lysine-specific demethylase-1 (LSD1) is a histone demethylase critical for self-renewal of malignant hematopoietic stem cells and for maturation of progenitor cells. Bomedemstat is an oral LSD1 inhibitor clinically active in patients with myeloproliferative neoplasms (MPN) and has shown clinical activity as a single-agent in patients with MF. Aims This is an ongoing, open-label, Phase 2 study of the combination of bomedemstat and ruxolitinib in treatment-naïve patients with MF or those with a sub-optimal response to ruxolitinib. The objectives of this are to evaluate the safety and tolerability of the combination, the optimal dosing of bomedemstat in this regimen, and to assess the efficacy of the combination as assessed by spleen size reduction and symptom reduction using the Myelofibrosis Symptom Assessment Form (MFSAF). Methods Cohort A is comprised of patients with a sub-optimal response to an adequate trial of ruxolitinib defined as splenomegaly not reduced by &amp;gt;35% from baseline or symptoms scores that have not improved by &amp;gt;50%. Cohort A patients must have been on a stable dose of ruxolitinib for ≥8wks. Cohort B is comprised of treatment-naïve patients with MF who require treatment per guidelines. Patients in Cohort A remain on the entry dose of ruxolitinib while Cohort B patients received a starting ruxolitinib dose of 10 mg BID throughout the study. All patients received concomitantly, a starting dose of bomedemstat of 0.4mg/kg/d. Dose adjustments up were allowed every 4 weeks to achieve a target platelet count of 50 x 10 9/L (40-90 x 10 9/L range) Down titrations could be made at any time in the interest of patient safety. Results At the data cut-off of 30 June 2023, 16 men and 16 women with a median age of 64 (range: 47-81) years were enrolled. Case distribution was PMF, N=19 (59.4%); PPV-MF, N=7 (21.9%); and PET-MF, N=6 (18.8%). Mutational profile of driver genes was JAK2 V617F, N=24 (75%); JAK2 exon 12, N=1 (3.1%); and CALR mutations, N=7 (21.9%). Six patient (18.8%) harbored high-molecular risk (HMR) mutations ( ASXL N =4; EZH2, N=2). At enrollment, the median white blood cell count (WBC), hemoglobin (Hb), platelet count, and lactate dehydrogenase (LDH) were 10.21 x 10 9/L (2.4-50.8 x 10 9/L), 9.4 g/dL (6.7-12.1g/dL), 215 x 10 9/L (100-906 x 10 9/L) and 504 IU/L (107-2174 UL), respectively. Ten patients (31.2%), 19 patients (59.4%) and 3 patients (9.4%) belonged to the Dynamic International Prognostic Scoring System (DIPSS) high, intermediate-2 and intermediate-1 risk categories, respectively. The median spleen size was 5cm (5-16cm) below left costal margin (BLCM). Twenty-four patients were enrolled in Cohort A with a median treatment duration of ruxolitinib of 128 (13-668) weeks. Cohort B has enrolled 8 patients. The median duration of ruxolitinib + bomedemstat was 12 (1-26) weeks. In 20 evaluable patients at Week 12 (Cohort A, N=17; Cohort B, N=3), 12 patients (60%) had stable ( ∆&amp;lt;± 1.0 g/dL) or improved Hb (&amp;gt;1.0 g/dL) (Cohort A: 11/17, 64.7%; Cohort B: 1/3, 33.3%), 5 patients (25%) had ≥50% reduction in MF-SAF Total Symptom Score (TSS) (Cohort A: 4/17, 23.5%; Cohort B: 1/3, 33.3%) and 18 patients (65%) had ≥ 30% spleen length reduction (Cohort A: 15/17, 88.2%; Cohort: 3/3, 100%) (Figure 1A-C). In six patients evaluable for molecular responses by droplet-digital polymerase chain reaction at Week 12, 4 patients (67%) had reductions in JAK2 V617F allele frequencies with 1 patient (17%) having ≥50% reduction. The most common non-hematologic adverse events (AEs) were diarrhea (Grade 1-2, N=16; Grade 3-4, N=0); malaise (Grade 1-2, N= 6; Grade 3-4, N=0); oedema (Grade 1-2, N=7; Grade 3-4, N=0) and dysgeusia (Grade 1-2, N=5; Grade 3-4, N=0). There were no safety signals, dose-limiting toxicities, or deaths related to drug. Conclusions These early results suggest that the addition of bomedemstat to a ruxolitinib regimen is well tolerated, improves splenomegaly and symptom scores, and stabilizes hemoglobin both in the frontline and second-line setting. Enrollment in ongoing.

Pitfalls of using polymerase chain reaction-based assays for JAK2 and CALR exon 9 variant testing in myeloproliferative neoplasms: Knowing when to go the extra mile!

The BCR::ABL1 negative myeloproliferative neoplasms are sequentially tested for JAK2 p.V617F, followed by CALR exon 9 pathogenic variants. Historically, these variants were thought to be mutually exclusive. However, recent reports indicate coexisting JAK2 p.V617F and CALR exon 9 somatic variants. Analysis of JAK2 p.V617F and CALR exon 9 variant was performed by polymerase chain reaction (PCR)-based assays. Subsequent testing was performed on the Genexus integrated sequencer (ThermoFisher) using the Oncomine myeloid assay GX v2. CALR exon 9 variants were positive in 3 cases, while 2 were positive for JAK2 p.V617F on PCR-based assays. Next-generation sequencing confirmed the JAK2 P.V617F status in all cases. CALR variants resulting in in-frame deletions were identified in 2 cases at a variant allele frequency of 52.16% and 50.91%, while the third case had an intronic CALR variant c.-48G>A at a variant allele frequency of 51.1%. Thus, CALR variants in all 3 cases were interpreted as potentially germline. Of the 228 cases that underwent JAK2 p.V617F and CALR cotesting in the past 2 years, only these 2 cases were positive for both JAK2 p.V617F and CALR exon 9 variants. These cases highlight the importance of understanding the pitfalls of molecular techniques in current practice.

FREQUENCY OF CLAR AND JAK2 MUTATIONS IN SUDANESE CHRONIC MYELOID LEUKEMIA PATIENTS WITH PHILADELPHIA-POSITIVE DISEASE

Background: It is well-established that myeloproliferative diseases coexist with CLAR and JAK2. In Ph+ chronic myeloid leukemia (CML), only a few case reports indicate the existence of CLAR, JAK2V617F, and JAK2 exon 12 mutations. Methods: This study examined CALR and JAK2 mutation profiles in Sudanese Chronic Myeloid Leukemia patients with Philadelphia-positive patients. Blood samples were collected from 100 patients with Ph+ CML chromosomes. Results for the JAK2V617F mutation were confirmed using the TaqMan® Mutation Detection Assay, and the four common mutations on exon 12 and CLAR mutations were confirmed using allele-specific PCR (AS-PCR) and Sanger sequencing. Results: CML patients with CALR frameshift mutations were detected in two patients (2%), patients with JAK2 exon 12 mutations were found in two patients (2%), and patients with JAK2V617F mutations made up 4 (4%) of the total CML patients. No significant relationships existed between mutations and age, WBC, RBC, Hb, HCT, or platelet parameters. Patients with CLAR, JAK2 exon 12, and JAK2V617F mutations have normal leukocyte counts and lower values compared to triple-negative Ph+ CML, but these differences are not statistically significant (p values for each 0.084, 0.173, and 0.072). Conclusion: It is conceivable for Ph+ CML and all mutations to coexist.

JAK2 exon 12 variants in vietnamese patients with JAK2 V617F-negative primary myelofibrosis

Primary myelofibrosis is the severe form of myeloproliferative neoplasms that causes scar tissue in the bone marrow, leading to low production of blood cells and thus, life span shortening. Besides the most common variant JAK2 V617F, the association between these disorders with other variants in the JAK2 gene, especially the exon 12 variants have been poorly studied. In our research, the JAK2 exon 12 variants were detected by amplification and sequencing from genomic samples of five cases with V617F-negative primary myelofibrosis. Results showed that among 5/14 primary myelofibrosis patients with V617F-negative profile, only two patients carried exon 12 variants (JAK2 c.1592A&gt;G p.H531R, and c.1613A&gt;C p.H538P). In silico analysis indicated that the variant c.1613A&gt;C p.H538P was novel and potentially pathogenic. The positioning demonstration by Missense3D tools indicated that this variant localized in the proximity to the pathogenic variant V617F, suggesting a potential effect on the enzymatic activity of Janus kinase 2. This initial data can be used as a genetic diagnostic criterion for myeloproliferative neoplasms. Nonetheless, the effect of p.H538P needs to be verified by further investigations.

SRSF2-P95H decreases JAK/STAT signaling in hematopoietic cells and delays myelofibrosis development in mice.

Heterozygous mutation targeting proline 95 in Serine/Arginine-rich Splicing Factor 2 (SRSF2) is associated with V617F mutation in Janus Activated Kinase 2 (JAK2) in some myeloproliferative neoplasms (MPNs), most commonly primary myelofibrosis. To explore the interaction of Srsf2P95H with Jak2V617F, we generated Cre-inducible knock-in mice expressing these mutants under control of the stem cell leukemia (Scl) gene promoter. In transplantation experiments, Srsf2P95H unexpectedly delayed myelofibrosis induced by Jak2V617F and decreased TGFβ1 serum level. Srsf2P95H reduced the competitiveness of transplanted Jak2V617F hematopoietic stem cells while preventing their exhaustion. RNA sequencing of sorted megakaryocytes identified an increased number of splicing events when the two mutations were combined. Focusing on JAK/STAT pathway, Jak2 exon 14 skipping was promoted by Srsf2P95H, an event detected in patients with JAK2V617F and SRSF2P95 co-mutation. The skipping event generates a truncated inactive JAK2 protein. Accordingly, Srsf2P95H delays myelofibrosis induced by the thrombopoietin receptor agonist Romiplostim in Jak2 wild-type animals. These results unveil JAK2 exon 14 skipping promotion as a strategy to reduce JAK/STAT signaling in pathological conditions.

JAK2/STAT5 Pathway Mutation Frequencies in South African BCR/ABL Negative MPN Patients.

Mutations in JAK2/STAT5 proliferation pathway genes are key in the diagnosis of myeloproliferative neoplasms (MPNBCR/ABLneg), with JAK2V617F being found in 50-97% of MPNBCR/ABLneg subtypes. Low JAK2V617F positivity at our facility suggested that our South African MPNBCR/ABLneg population may have a different mutational landscape. We aimed to determine the JAK2/STAT5 mutation frequencies associated with our local MPNBCR/ABLneg population, thus determining the relevance of these molecular tests in this group. We also investigated the haematopathological relevance of each test request, to assess testing practises. This study involved the retrospective audit of 886 patients for whom JAK2V617F mutation testing had been requested for a suspected MPN diagnosis. FBC indices, erythropoietin levels and bone marrow biopsy results were used to classify the patients. JAK2V617F negative patient DNA was tested for calreticulin (CALR) exon9, myeloproliferative leukaemia protein (MPL) codon515 and JAK2 exon12 mutations. Only 23% of the patients demonstrated JAK2V617F positivity, with an additional 29 cases of CALR/MPL mutations being detected. Mutations were only detected in patients with abnormal FBC indices, as expected, yet 37% of the test requests were not associated with abnormal parameters at the time of testing. Mutation frequencies were as follows: Polycythaemia Vera: 97% JAK2V617F/3% (JAK2, CALR, MPL) triple negative; Essential thrombocythemia: 72% JAK2V617F/23%CALR/5%triple negative; Primary Myelofibrosis: 78%JAK2V617F/16%CALR/6%triple negative. Our study demonstrated that our MPNBCR/ABLneg patients have a similar genetic landscape to other MPN populations, with >93% being able to be diagnosed by testing for the JAK2V617F and CALR exon9 mutations alone. Adoption of the WHO 2016 guidelines is recommended to guide testing practices.

JAK 2 NEGATIVE POLYCYTHEMIA VERA IN A TERTIARY CARE CENTER IN WEST UP POPULATION IN INDIA :A RARE PRESENTATION OF 5 CASES

Introduction: Polycythaemia vera (PV) belongs to the group of myeloproliferative neoplasms with an excessive increase in hemoglobin levels.(1). It has been seen that JAK2 V617F mutation present in 80-90% of MPNs and JAK2 exon12 mutations are seen in 4%-5% cases of MPNs like PV.As per an Indian data the JAK2V617F mutational frequency in Indian population was 81.8% for PV, which was different from that reported in western literature as more than 95% for PV.Activation of JAK2 by either point mutation or fusion protein causes activation of the JAK-STAT pathway. While mutations in JAK2 are reported in numerous MPN phenotypes, exon 12 mutations specifically result in erythrocytosis due to increased EPO signalling. In India, the incidence of JAK2-negative polycythemia is relatively high, reaching up to 18%. (2,3) Case series: Case 1-A 21-year male presented to the hematology OPD with complains of paresthesias and off and on headache for the past 6 months. He was on multiple symptomatic medications but to no relief. On routine investigations it was seen that he had a persistent hemoglobin level fluctuating between 17.5gm/dl and 18.5 gm/dl. He has iron deficiency for which he is on single oral iron tablet. No definite organomegaly was seen. In hematology OPD he was investigated for polycythemia vera keeping in mind the WHO criterias.His Serum EPO levels are within normal range,JAK2 V617F/exon 12mutation analysis is negative.A bone marrow aspiration and biopsy study done shows Hypoplastic marrow for age with erythroid predominance. In view of clinical suspicion of JAK 2 negative PV he is being treated with ecosprin, phlebotomy every 3 months and supplemental iron orally. The patient is clinically relieved of his symptoms of peripheral neuropathy. His last hemoglobin value is stable at 16.5gm/dl.Case 2-A 32 -year male presented to hematology OPD with mild headache and weakness for 6 months. A routine CBC investigation showed a high hemoglobin level of 18.4 gm/dl. Mildly raised RBC count was also seen. A subnormal serum EPO levels of 3.7 mIU/Ml (4.3-29.0 mIU/ML) was seen. JAK 2V617F/exon 12 mutation analysis was negative. The patient has been started on ecosprin and phlebotomy every 3 months and is symptomatically relieved.Case 3- A 29-year male presented to hematology OPD with paresthesias and weakness for 3 months. A routine CBC investigation showed a high hemoglobin level of 19.7 gm/dl. Mildly raised RBC count was also seen. Rest all parameters were within normal limits. On examination no hepatosplenomegaly or lymphadenopathy was seen. A low serum EPO levels of &lt;1 mIU/Ml (4.3-29.0 mIU/ML) was seen. JAK 2V617F/exon12 mutation analysis was negative. The patient has been started on ecosprin and phlebotomy every 3 months and is symptomatically relieved. Case4-33 year male presented to OPD with fatigue and paresthesias.CBC showed increased hemoglobin of 18gm/dl.Patient was a non-smoker.Vitamin B12 was&gt;1000gm/dl.Bone marrow showed mildly predominant myeloid series.JAK2 mutation profile was negative but the patient responded to phlebotomy.Case5:A 28 year female had recurrent headaches however MRI and other investigations were normal. A serum EPO level done on suspicion of PV showed subnormal ranges.Bone marrow was reported as reactive.JAK2 mutation analysis was negative however patient responds to ecosprin and hyroxyurea. Conclusion-All five cases that presented to the department had been undiagnosed before they reached our setup. The unique feature of all these cases was negativity for both JAK2V617F as well as JAK2 exon 12 mutation despite its clinical behaviour being that of PV .These cases are being actively managed as low risk polycythemia vera and since the start of the treatment comprising of phlebotomy once every 3 months their hemoglobin and hematocrit concentrations are maintained.No cytoreductive therapy is being given .Such unique presentations need to be reported and discussed extensively.

JAK 2 NEGATIVE POLYCYTHEMIA VERA IN A TERTIARY CARE CENTER IN WEST UP POPULATION IN INDIA :A RARE PRESENTATION OF 5 CASES

Introduction: Polycythaemia vera (PV) belongs to the group of myeloproliferative neoplasms with an excessive increase in hemoglobin levels.(1). It has been seen that JAK2 V617F mutation present in 80-90% of MPNs and JAK2 exon12 mutations are seen in 4%-5% cases of MPNs like PV.As per an Indian data the JAK2V617F mutational frequency in Indian population was 81.8% for PV, which was different from that reported in western literature as more than 95% for PV.Activation of JAK2 by either point mutation or fusion protein causes activation of the JAK-STAT pathway. While mutations in JAK2 are reported in numerous MPN phenotypes, exon 12 mutations specifically result in erythrocytosis due to increased EPO signalling. In India, the incidence of JAK2-negative polycythemia is relatively high, reaching up to 18%. (2,3) Case series: Case 1-A 21-year male presented to the hematology OPD with complains of paresthesias and off and on headache for the past 6 months. He was on multiple symptomatic medications but to no relief. On routine investigations it was seen that he had a persistent hemoglobin level fluctuating between 17.5gm/dl and 18.5 gm/dl. He has iron deficiency for which he is on single oral iron tablet. No definite organomegaly was seen. In hematology OPD he was investigated for polycythemia vera keeping in mind the WHO criterias.His Serum EPO levels are within normal range,JAK2 V617F/exon 12mutation analysis is negative.A bone marrow aspiration and biopsy study done shows Hypoplastic marrow for age with erythroid predominance. In view of clinical suspicion of JAK 2 negative PV he is being treated with ecosprin, phlebotomy every 3 months and supplemental iron orally. The patient is clinically relieved of his symptoms of peripheral neuropathy. His last hemoglobin value is stable at 16.5gm/dl.Case 2-A 32 -year male presented to hematology OPD with mild headache and weakness for 6 months. A routine CBC investigation showed a high hemoglobin level of 18.4 gm/dl. Mildly raised RBC count was also seen. A subnormal serum EPO levels of 3.7 mIU/Ml (4.3-29.0 mIU/ML) was seen. JAK 2V617F/exon 12 mutation analysis was negative. The patient has been started on ecosprin and phlebotomy every 3 months and is symptomatically relieved.Case 3- A 29-year male presented to hematology OPD with paresthesias and weakness for 3 months. A routine CBC investigation showed a high hemoglobin level of 19.7 gm/dl. Mildly raised RBC count was also seen. Rest all parameters were within normal limits. On examination no hepatosplenomegaly or lymphadenopathy was seen. A low serum EPO levels of &lt;1 mIU/Ml (4.3-29.0 mIU/ML) was seen. JAK 2V617F/exon12 mutation analysis was negative. The patient has been started on ecosprin and phlebotomy every 3 months and is symptomatically relieved. Case4-33 year male presented to OPD with fatigue and paresthesias.CBC showed increased hemoglobin of 18gm/dl.Patient was a non-smoker.Vitamin B12 was&gt;1000gm/dl.Bone marrow showed mildly predominant myeloid series.JAK2 mutation profile was negative but the patient responded to phlebotomy.Case5:A 28 year female had recurrent headaches however MRI and other investigations were normal. A serum EPO level done on suspicion of PV showed subnormal ranges.Bone marrow was reported as reactive.JAK2 mutation analysis was negative however patient responds to ecosprin and hyroxyurea. Conclusion-All five cases that presented to the department had been undiagnosed before they reached our setup. The unique feature of all these cases was negativity for both JAK2V617F as well as JAK2 exon 12 mutation despite its clinical behaviour being that of PV .These cases are being actively managed as low risk polycythemia vera and since the start of the treatment comprising of phlebotomy once every 3 months their hemoglobin and hematocrit concentrations are maintained.No cytoreductive therapy is being given .Such unique presentations need to be reported and discussed extensively.

Clinicopathologic characteristics of myeloproliferative neoplasms with JAK2 exon 12 mutation

The presence of JAK2 exon 12 mutation was included by the 2016 World Health Organization (WHO) Classification as one of the major criteria for diagnosing polycythemia vera (PV). Few studies have evaluated the clinical presentation and bone marrow morphology of these patients and it is unclear if these patients fulfill the newly published criteria of 5th edition WHO or The International Consensus Classification (ICC) criteria for PV. Forty-three patients with JAK2 exon 12 mutations were identified from the files of 7 large academic institutions. Twenty patients had complete CBC and BM data at disease onset. Fourteen patients met the diagnostic criteria for PV and the remaining six patients were diagnosed as MPN-U. At diagnosis, 9/14 patients had normal WBC and platelet counts (isolated erythrocytosis/IE subset); while 5/14 had elevated WBC and/or platelets (polycythemic /P subset). We found that hemoglobin and hematocrit tended to be lower in the polycythemia group. Regardless of presentation (P vs IE), JAK2 deletion commonly occurred in amino acids 541–544 (62 %). MPN-U patients carried JAK2 exon 12 mutation, but did not fulfill the criteria for PV. Half of the patients had hemoglobin/hematocrit below the diagnostic threshold for PV, but showed increased red blood cell count with low mean corpuscular volume (56–60 fL). Three cases lacked evidence of bone marrow hypercellularity. In summary, the future diagnostic criteria for PV may require a modification to account for the variant CBC and BM findings in some patients with JAK2 exon 12 mutation.

The Clinical Profile of JAK2 Negative,Normal Erythropoeitin,Normal Arterial Oxygen Saturation Erythrocytosis in an Indian Tertiary Centre

Introduction: Polycythemia Vera (PV) is a myeloproliferative syndrome characterized by JAK2 mutation with evidence of panmyelosis in the bone marrow [WHO 2016]. PV has risk of thrombosis and transformation to myelofibrosis /leukemia. Etiologies enlisted for JAK2 negative erythrocytosis include high-oxygen affinity hemoglobin variants, 2,3 biphosphoglycerate deficiency, and germline (e.g., PHD2, HIF2A, VHL) or EPO signaling (e.g., EPOR) mutations. Investigating for such causes is not feasible in rural India. JAK2 negative erythrocytosis is the category comprising these mutations and idiopathic causes. The treatment recommendations for JAK2 negative erythrocytosis is limited. The risk of thrombosis in this group is unknown. We present the clinical profile of subgroup of JAK2 Negative erythrocytosis with normal Erythropoietin [EPO] and normal arterial oxygen saturation [PaO2] from a tertiary care center in India. Method of study: Retrospective analysis of all the patients presented to the hematology outpatient clinic with high Hb /Hematocrit >16.5/49 for males and >16/48 for females from August 2019 to November 2021 were evaluated. Secondary causes evaluated. They underwent clinical examination, Complete blood count, ABG analysis for arterial oxygen saturation, Serum EPO estimation by chemiluminescence immunoassay [Normal: 2.6 - 18.5 mIU/mL], blood JAK2 V617F and JAK2 exon 12 mutation analysis by NGS at Medgenome Labs Pvt Limited, Bengaluru, Unilateral bone marrow aspiration and biopsy if willing. Inclusion criteria: 1.Hb /HCT >16.5gram%/ 49 for men and >16gram% /48 for women. Exclusion Criteria: 1.History of smoking, cyanosis or obstructive sleep apnea, COPD or cyanotic heart disease or high altitude, anabolic steroids. 2.Family history. 3.PaO2 below normal. 4.WBC > 11000/microliter, Platelets > 450000/microliter. 5.Palpable splenomegaly. 6.Erythropoietin levels <2.6mIU/ml or>8.5mIU/ml. 7.Jak2 V617F or Exon 12 mutation in NGS. 8.Panmyelosis in bone marrow [WHO 2016 criteria] Results: Total 256 patients were with elevated Hemoglobin.122 patients were excluded in view of meeting one of the exclusion criteria. Additional 58 patients were excluded because of lack of JAK2 mutational analysis. 76 patients who met the inclusion criteria of JAK2 negative erythrocytosis with normal EPO and normal PaO2.75 patients were males, mean age was 40 years [Range:15 -75]. Mean Hemoglobin at presentation was 18gram% [Range:16.8 to 22]. Mean erythropoietin was 6.69mIU/ml [Range 3-16.3]. The median follow up was for 8 months [Range:1 month to 24 months]. 37 patients were asymptomatic at presentation, for whom high Hb was detected while screening for blood donation or as a part of routine checkup. 16 patients developed thrombosis at the presentation. Median age of the patient's developing thrombosis was 42 [range 24 to 68 years].8 patients developed stroke,3 patients developed coronary artery disease,4 patients developed venous thrombosis.15 patients had hypertension at presentation. Other presenting symptoms were headache, redness of eyes, giddiness. Only 13 patients underwent bone marrow examination, in which 9 had normal bone marrow, 4 had isolated erythrocytosis. 47 patients took aspirin regularly. 32 patients underwent phlebotomy once a month if Hb/HCT >15gram/45. 13 of the 16 patients with thrombosis at presentation were continuing aspirin and were adhering to phlebotomy during follow up.3 patients received hydroxyurea as they were not tolerating phlebotomy. No patients developed new thrombotic events during the follow up. There was no correlation with level of Hb or EPO with thrombosis. Discussion: Our retrospective of JAK2 negative erythrocytosis data showed that the majority of patients were male,48 % patients were asymptomatic and had no thrombotic complications during the follow up. 21% developed thrombotic events at presentation. The duration of follow up is short in our study. Ideal treatment for thrombosis in this group needs further clinical trials. Treatment protocol for asymptomatic patients also need further clinical trials. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Erythropoietin Levels in Patients with Polycythemia Vera and Secondary Erythrocytosis

BACKGROUND: Polycythemia Vera (PV) is a myeloproliferative neoplasm characterized by uncontrolled proliferation of erythrocytes with frequent co-stimulation of myeloid and megakaryocyte progenitor cells. Prior to the utilization of molecular testing, subnormal or low erythropoietin (EPO) levels were an important component in the diagnosis of PV. In 2005, the somatic JAK2 V617Fmutation was discovered to be present in greater than 95% of patients with PV. In turn, the 2008 WHO diagnostic criteria revision added the JAK2 mutation to the major criteria. The current WHO criteria for the diagnosis of PV designates the major criteria to be a hemoglobin greater than 16.5 g/dL in men and 16 g/dL in women (or a hematocrit greater than 49% in men and 48% in women), a bone marrow biopsy demonstrating hypercellularity and trilineage panmyelosis, and the presence of a JAK2 V617F or exon 12 mutation. A subnormal EPO level is a minor criterion. Based on these, PV can be diagnosed by the presence of all three major criteria, or the first two major criteria with a subnormal EPO level. Subnormal EPO levels have been reported to be found in only around 30% of patients otherwise meeting the diagnostic criteria for PV. The sensitivity and specificity of a subnormal EPO level in the diagnosis of PV has been shown to be 64% and 96%, respectively. The diagnostic value of the EPO level is confounded by the co-occurrence of comorbidities such as obstructive sleep apnea, chronic obstructive pulmonary disease, tobacco use, and obesity. As a result, controversies exist as to the role of EPO in the diagnosis of PV. In this study, we aimed to describe the EPO level in patients with primary erythrocytosis (or PV) and secondary erythrocytosis in a Los Angeles safety-net hospital where these comorbidities are prevalent. We also examined the prevalence of these comorbidities in both patient populations. METHODS: We performed a retrospective chart review of all patients aged greater than 18 years who presented to Harbor-UCLA Medical Center between 2015 and 2021 with the diagnosis of erythrocytosis using the International Classification of Disease-specific codes. We excluded patients who were erroneously given the diagnosis code for erythrocytosis when no erythrocytosis was documented or patients who had one documented hemoglobin level above the normal reference range with spontaneous resolution and no further work up. Patient demographics, baseline characteristics, laboratory values, bone marrow biopsy results, molecular testing, and comorbidities were recorded. RESULTS: There was a total of 141 patients who met the inclusion criteria (Table 1). Of these, 12 (8.5%) had the diagnosis of primary erythrocytosos or PV. Of those diagnosed with PV, all 12 (100%) had the JAK2 V617Fmutation. The average hemoglobin and hematocrit of patients with PV and secondary erythrocytosis was 17.8 g/dL and 54% and 18.1 g/dL and 57%, respectively. The average EPO for those with primary and secondary erythrocytosis was 3.4 mIU/mL and 23.7 mIU/mL, respectively (normal 2.6-18.5 mIU/mL). Of those with primary polycythemia, 6/11 (55%) had a subnormal EPO level at diagnosis. The average age of those with PV and secondary erythrocytosis was 69 years and 53 years, respectively. The average BMI for those with PV and erythrocytosis was 27.5 and 32.5, respectively. In those with secondary erythrocytosis versus PV, the most common comorbidities were pulmonary disease (58.3% versus 41.7%), smoking (36.7% versus 41.7%), heart disease (23.0% versus 25%), kidney disease (21.6% versus 25%), and testosterone use (5.0% versus 0%) (Table 2). CONCLUSIONS: In this study, we found that most patients with PV had a low EPO level at diagnosis with over half having a subnormal EPO level. In contrast, very few patients with secondary erythrocytosis had a subnormal EPO level. The prevalence of comorbidities was common in both primary and secondary erythrocytosis. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal