A 27-Gene NGS Panel in Primary Myelofibrosis Identifies ASXL1, CBL, RUNX1 and SRSF2 Mutations As Being Unfavorable and Absence of Any Non-Driver Mutation As Being Favorable to Survival

Abstract Background : In primary myelofibrosis (PMF), ̴ 88% of patients harbor one of three "driver" mutations, with mutational frequencies of approximately 60%, 22% and 6% for JAK2, CALR and MPL, respectively. Other "non-driver" mutations have also been described in PMF and some of them and their number have been associated with inferior survival (Leukemia. 2014;28:1804). We applied next generation sequencing (NGS) with a broader panel of MPN-relevant genes, in order to identify additional mutations of prognostic relevance as well as obtain additional information regarding the prognostic value of 'number of mutations'. Methods: Targeted capture assays were carried out on bone marrow or whole blood DNA specimens obtained at time of referral for the following genes: TET2, DNMT3A, IDH1, IDH2, ASXL1, EZH2, SUZ12, SRSF2, SF3B1, ZRSR2, U2AF1, PTPN11, Tp53, SH2B3, RUNX1, CBL, NRAS, JAK2, CSF3R, FLT3, KIT, CALR, MPL, NPM1, CEBPA, IKZF, and SETBP1. Paired-end indexed libraries were prepared from individual patient DNA using the NEB Next Ultra Library prep protocol on the Agilent Bravo liquid handler (NEB, Ipswich, MA/Agilent Technologies Inc, Santa Clara, CA). Capture libraries were assembled according to Nimblegen standard library protocol (Roche Nimblegen, Inc, Basel, Switzerland). Base-calling was performed using Illumina's RTA version 1.17.21.3. Genesifter® software was utilized (PerkinElmer, Danvers, Massachusetts) to analyze targeted sequence data. Nucleotide variants were called using the Genome Analysis Toolkit (GATK-Broad Institute, Cambridge, MA). Specific variants were deemed as mutations if they are associated with a hematologic malignancy (as identified by COSMIC database), or if they have not been associated with a dbSNP. Results: 180 PMF patients were evaluated (median age 63 years; 65% males). DIPSS-plus risk distribution was 32% high, 38% intermediate-2, 17% intermediate-1 and 13% low. Driver mutation distribution was 62% JAK2, 22% CALR, 9% triple-negative and 7% MPL. Karyotype was abnormal in 41% of patients and unfavorable in 12%. Mutations other than JAK2, CALR or MPL (i.e. "non-driver" mutations) were seen in 150 (83%) patients including 88% of "triple-negative" cases. 62 (34%) patients harbored one, 55 (31%) two, 16 (9%) three and 17 (10%) four or more. Mutational frequencies were: ASXL1 36%, TET2 18%, SRSF2 17%, U2AF1 17%, ZRSR2 11%, SF3B1 10%, DNMT3A 9%, CEBPA (9%), Tp53 7%, SETBP1 6%, CBL 5%, IDH1/2 5%, SH2B3 4%, CSF3R 4%, NRAS 4%, RUNX1 3% and ≤2% for SUZ12, KIT, PTPN11, NPM1 and EZH2. DIPSS-plus high/intermediate-2 risk patients displayed higher number of mutations (p=0.0004) and higher mutational frequencies for ASXL1 (p=0.02), SRSF2 (p=0.004) and CBL (p=0.02). Associations noted included JAK2 with U2AF1 (p=0.03), unfavorable karyotype with CBL (p=0.01) and normal karyotype with ZRSR2 mutations (p=0.04). At a median follow-up of 4 years, 111 (62%) deaths were documented. For examination of impact on survival, we considered 'number of mutations' and specific mutations with >2% frequency. Accordingly, in univariate analysis, survival was adversely affected by 'number of mutations' (Figure 1) and presence of ASXL1, SRSF2, IDH1/2, U2AF1, RUNX1 and CBL mutations. For multivariable analysis, we considered three categories (zero, 1-3 and ≥4) for number of mutations based on the results from univariate analysis (Figure 1); the results showed ≥4 mutations, 1-3 mutations, RUNX1, CBL, ASXL1 and SRSF2 mutations were independently associated with shortened survival; the respective HR (95% CI) were 4 (1.4-11.1), 3 (1.3-6.8), 2.9 (1.1-8.1), 2.8 (1.3-6.3), 1.8 (1.2-2.7) AND 1.7 (1.03-2.7). When the multivariable analysis was repeated including only the 150 patients with at least one non-driver mutation, the 'number of mutations' was no longer significant (p=0.35) but ASXL1, CBL, RUNX1 and SRSF2 mutations retained their significance. The prognostic relevance of ASXL1 and CBL continued to be apparent even after the addition of DIPSS-plus and driver mutation profile to the multivariable model. Conclusions: Mutations other than JAK2, CALR or MPL occur in more than 80% of patients with PMF, including those with "triple-negative" driver mutational status. The absence of such mutations is independently favorable for survival while the prognostic effect of their presence is influenced by ASXL1, CBL, RUNX1 and SRSF2 mutations. Figure 1. Figure 1. Disclosures Pardanani: Stemline: Research Funding.

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Driver Mutations and Prognosis in 502 Patients with Essential Thrombocythemia

Blood ◽

10.1182/blood.v126.23.1599.1599 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1599-1599 ◽

Cited By ~ 1

Author(s):

Yoseph Elala ◽

Terra L. Lasho ◽

Naseema Gangat ◽

Christy Finke ◽

A Kamel Abou Hussein ◽

...

Keyword(s):

Platelet Count ◽

Survival Data ◽

Triple Negative ◽

Univariate Analysis ◽

Multivariable Analysis ◽

Driver Mutations ◽

Mutational Status ◽

Age And Sex

Abstract Background : In essential thrombocythemia (ET) , ̴ 85% of patients harbor one of three "driver" mutations, with mutational frequencies of approximately 58%, 23% and 4%, for JAK2, CALR and MPL, respectively; ̴ 15% are wild type for all three mutations and are operationally referred to as "triple negative" (Blood. 2014;124:2507). In one of the original descriptions on CALR mutations, CALR -mutated patients with ET, compared to their JAK2-mutated counterparts, were reported to have better survival (NEJM. 2013;369:2379). However, this observation was not supported by subsequent studies while other reports suggested differential prognostic effect from distinct CALR variants in myelofibrosis (Blood. 2014;124:2465). In this study, we sought to clarify the impact of all three mutations, and CALR variants, on overall (OS), myelofibrosis-free (MFS) and leukemia-free (LFS) survival. Methods: Patientswere selected from our institutional database of myeloproliferative neoplasms, based on availability of mutational status inforomation. ET diagnosis was according to WHO criteria (Blood. 2009;114:937). Published methods were used for CALR, JAK2 and MPL mutation analyses and determination of CALR variants (Blood. 2014;124:2465). Kaplan-Meier survival analysis was considered from the date of diagnosis to date of death or last contact. MFS and LFS calculations considered fibrotic or leukemic transformation events as uncensored variables, respectively. Cox proportional hazard regression model was used for multivariable analysis. Results : A total of 502 patients (median age 59 year; 61% females) met study eligibility criteria. Median levels of hemoglobin, platelet count and leukocyte counts were 13.7 g/dL, 893 x 10 (9)/L and 8.8 x 10(9)/L, respectively. All patients were annotated for JAK2/CALR/MPL mutations as well as CALR variants; 324 harbored JAK2, 111 CALR and 13 MPL mutations; 54 patients were triple-negative. The 111 CALR-mutated patients included type 1 (n=55), type 2 (n=41) or other (n=15) CALR variants. At a median follow-up time of 9.9 years, 172 (34.3%) deaths, 42 (8.4%) fibrotic progressions, 15 (3%) blast transformations and 12 (2.4%) polycythemic conversions were documented. In univariate analysis, survival data appeared significantly better in "triple negative" patients (median not reached) and inferior in MPL-mutated cases (median 8.5 years) whereas median survival times were similar for JAK2 (18.5 years) and CALR (22.1 years) mutated cases (Figure 1; p=0.0006). However, the difference in survival was no longer apparent (p=0.60) during multivariable analysis that included age and sex, which are known to differentially cluster with specific driver mutations; in the current study, median age/sex distributions for "triple-negative", CALR, JAK2 and MPL mutated cases were 44 years/72% females, 48 years/46% females, 60 years/65% females, 70 years/46% females, respectively (p=<0.0001/0.0007). Of note, both age and sex were independently predictive of shortened survival. OS data remained unchanged when CALR-mutated patients were further stratified into type 1 vs type 2 vs other CALR variants, with similar survival data between the three CALR mutation groups (p=0.98). In univariate analysis, MPL-mutated patients were significantly more prone to fibrotic progression (Figure 2; p=0.0083). The prognostic relevance of MPL mutations to MFS remained significant when age and sex were included in multivariable analysis (p=0.008). In the current cohort, univariate analysis identified lower hemoglobin and lower platelet count as the only other risk factors for fibrotic progression. Multivariable analysis confirmed the independent prognostic relevance of MPL mutations (p=0.003), lower hemoglobin level (p=0.0009) and lower platelet count (p=0.0094) for MFS. There was no significant difference in LFS among the four driver mutational categories (p=0.9): 9 events in JAK2, 6 in CALR, none in triple negative and none in MPL mutated cases. Among the 6 leukemic transformations in CALR-mutated cases, three were type 1, two type 2, and one other CALR variants. Conclusions : Age- and sex-adjusted survival is similar among ET patients with JAK2 vs CALR vs MPL vs "triple-negative" mutational status. Survival is also similar between patients with distinct CALR variants. MPL -mutated patients with ET might be at a higher risk of fibrotic progression. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Pardanani: Stemline: Research Funding.

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The clinical and prognostic relevance of driver mutations in 203 Taiwanese patients with primary myelofibrosis

Journal of Clinical Pathology ◽

10.1136/jclinpath-2017-204829 ◽

2017 ◽

Vol 71 (6) ◽

pp. 514-521 ◽

Cited By ~ 1

Author(s):

Ming-Chung Kuo ◽

Tung-Huei Lin ◽

Chien-Feng Sun ◽

Tung-Liang Lin ◽

Jin-Hou Wu ◽

...

Keyword(s):

Triple Negative ◽

Direct Sequencing ◽

Primary Myelofibrosis ◽

Driver Mutations ◽

Driver Genes ◽

Allele Burden ◽

Prognostic Relevance ◽

Mutational Status ◽

Length Changes

AimsWe investigated the clinical and prognostic relevance of the mutational status of driver genes with allele burden and endogenous erythroid colony (EEC) growth in 203 Taiwanese patients with primary myelofibrosis (PMF).MethodsPyrosequencing was used to detect JAK2V617F mutational status and measure allele burden, while MPL (exon 10) mutations were analysed by PCR assay and then by direct sequencing. CALR exon 9 mutations were first screened for length changes by GeneScan followed by sequencing. The allele burden of the mutated CALR gene was measured by pyrosequencing. The EEC assay was conducted using a serum-free culture system.ResultsThe frequencies of the three driver mutations and triple-negative status were similarly distributed between pre-PMF and overt PMF patients, except that pre-PMF patients had a higher incidence of CALR type 2/type-2 like mutations and a lower JAK2V617F allele burden. EEC growth and CALR mutations conferred favourable overall survival (OS). A lower JAK2V617F allele burden and grade 3 bone marrow fibrosis were associated with shorter OS and decreased leukaemia-free survival (LFS). Type 2/type 2-like CAL mutations were associated with better LFS compared with type1/type 1-like mutations. Patients with triple-negative mutation status had significantly worse OS and LFS. The allele burden of CALR mutations remained unchanged, while some JAK2V617F mutations showed clonal expansion in patients during secondary acute myeloid leukaemia transformation.ConclusionsOur study showed that EEC growth, a higher JAK2V617F allele burden and CALR mutations, especially type 2, were independent predictors for better outcomes in PMF. The allele burden of CALR mutations remained stable, but the allele burden of JAK2V617Fmutations was variable during leukaemia transformation.

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Targeted Next-Generation Sequencing in Polycythemia Vera and Essential Thrombocythemia

Blood ◽

10.1182/blood.v126.23.354.354 ◽

2015 ◽

Vol 126 (23) ◽

pp. 354-354 ◽

Cited By ~ 8

Author(s):

Ayalew Tefferi ◽

Terra L. Lasho ◽

Christy Finke ◽

Yoseph Elala ◽

Daniela Barraco ◽

...

Keyword(s):

Next Generation Sequencing ◽

Polycythemia Vera ◽

Essential Thrombocythemia ◽

Triple Negative ◽

Sequence Data ◽

Univariate Analysis ◽

Multivariable Analysis ◽

Driver Mutations ◽

Next Generation ◽

Generation Sequencing

Abstract Background : Polycythemia Vera (PV) is associated with JAK2 mutations. In essential thrombocythemia (ET), ̴ 85% of patients harbor one of 3 "driver" mutations, with frequencies of ̴ 58%, 23% and 4%, for JAK2, CALR and MPL, respectively; ̴ 15% are wild type for all three mutations and are referred to as "triple negative". We applied next-generation sequencing (NGS) with a 27-gene panel of myeloid malignancy-relevant genes, in order to describe the prevalence of "non-driver" mutations and their prognostic relevance in PV and ET. Methods: Targeted capture assays were carried out on bone marrow or whole blood DNA for the following genes: TET2, DNMT3A, IDH1, IDH2, ASXL1, EZH2, SUZ12, SRSF2, SF3B1, ZRSR2, U2AF1, PTPN11, Tp53, SH2B3, RUNX1, CBL, NRAS, JAK2, CSF3R, FLT3, KIT, CALR, MPL, NPM1, CEBPA, IKZF, and SETBP1.Paired-end indexed libraries were prepared using the NEBNext Ultra Library prep protocol (NEB, Ipswich, MA /Agilent Technologies Inc, Santa Clara, CA). Capture libraries were assembled according to Nimblegen standard library protocol (Roche Nimblegen, Inc, Basel, Switzerland). Base-calling was performed using Illumina's RTA version 1.17.21.3. Genesifter® software (PerkinElmer, Danvers, Massachusetts) was utilized to analyze targeted sequence data. Nucleotide variants were called using the Genome Analysis Toolkit (GATK -Broad Institute, Cambridge, MA). Specific variants were deemed as mutations if they are associated with a hematologic malignancy (COSMIC database), or if they have not been associated with a dbSNP. Results: 314 patients with PV (n =133; median age 64 years, 53% females) or ET (n =181; median age 58 years, 59% females) were evaluated. Median follow-up was 9.8 years for PV and 9.2 years for ET. During this time 59 (44%) deaths, 15 (11%) fibrotic and 5 (4%) leukemic transformations were documented for PV and the corresponding percentages for ET were approximately 33%, 8% and 2%. Driver mutation distribution was 98% JAK2 for PV and 52% JAK2, 24% CALR, 20% triple-negative and 4% MPL for ET. Polycythemia Vera Mutations other than JAK2, CALR or MPL were seen in 58 (44%) patients; 29% harbored one, 14% two and one 3 mutations. None of 3 JAK2 -unmutated cases expressed non-driver mutations. Mutational frequencies were 18% TET2, 11% ASXL1, 5% SH2B3, 3% SF3B1 and ≤2% SETBP1, IDH2, DNMT3A, CEBPA, CSF3R and SUZ12, SRSF2, ZRSR2, TP53, CBL, NRAS, RUNX1, KIT, PTPN11 and FLT3. "Number of mutations" significantly affected overall (OS; Figure 1) and myelofibrosis-free (MFS) survival; respective HR (95% CI) were 2.6 (1.3-5.2) and 1.7 (0.97-3.1) and 13.7 (2.9-63.4) and 5.1 (1.5-17.6) for ≥2 mutations and one mutation, respectively. OS was also adversely affected by SRSF2 (p=0.006) and RUNX1 (p=0.04) and borderline affected by TET2 (p=0.06), IDH2 (p=0.08), ASXL1 (p=0.19) and SF3B1 (p=0.19) mutations. In multivariable analysis, SRSF2 and RUNX1 retained significance whereas the others remained borderline significant. In both univariate and multivariable analyses, leukemia-free survival (LFS) was adversely affected by IDH2 and RUNX1 mutations. In univariate analysis, ASXL1, IDH2, RUNX1 and KIT mutations predicted fibrotic progression, whereas SETBP1 was of borderline significance (p=0.07); all, including SETBP1, were significant during multivariable analysis. Essential thrombocythemia Mutations other than JAK2, CALR or MPL were seen in 83 (46%) patients; 35% harbored one, 7% two and 4% three mutations; prevalence in JAK2, CALR, MPL mutated and triple-negative cases was 52%, 43%, 43% and 35%, respectively (p=0.52). Mutational frequencies were: 13% TET2, 11% ASXL1, 6% DNMT3A, 5% SF3B1, 4% CEBPA, 2% TP53, SH2B3, EZH2 and CSF3R and <2% for SETBP1, IDH2, SRSF2, ZRSR2, CBL, NRAS, RUNX1, U2AF1, KIT, PTPN11 and FLT3. "Number of mutations" significantly affected OS (Figure 2) but not MFS or LFS; HR (95% CI) for OS were 6.6 (2.5-17.8) for 3 mutations and 2.2 (1.3-3.9) for one or two mutations. In univariate analysis, survival was adversely affected by CBL, EZH2, SF3B1, SRSF2 and IDH2 mutations. In multivariable analysis, EZH2 and SF3B1 remained significant. Univariate analysis identified SETBP1 and SF3B1 mutations as risk factors for fibrotic progression and EZH2, TP53 and CSF3R mutations for leukemic transformation. Conclusions: "Non-driver" mutations occur in more than 40% of patients with PV or ET; the number of such mutations and presence of certain specific ones likely predict OS, MFS or LFS. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Pardanani: Stemline: Research Funding.

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U2AF1 Mutation Variants and Their Phenotypic and Prognostic Relevance in Primary Myelofibrosis

Blood ◽

10.1182/blood.v128.22.4248.4248 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4248-4248 ◽

Cited By ~ 1

Author(s):

Ayalew Tefferi ◽

Daniela Barraco ◽

Terra L. Lasho ◽

Christy Finke ◽

Sahrish Shah ◽

...

Keyword(s):

Univariate Analysis ◽

Multivariable Analysis ◽

Normal Karyotype ◽

Primary Myelofibrosis ◽

Older Age ◽

Severe Anemia ◽

Mutational Status ◽

Survival Effect

Abstract Background U2AF1 mutations occur in approximately 16% of patients with primary myelofibrosis (PMF) and were significantly associated with anemia, thrombocytopenia, older age, JAK2V617F, ASXL1 mutations and normal karyotype (Leukemia 2014;28:431); furthermore, U2AF1 mutations were associated with inferior survival in univariate but not multivariable analysis. In the current study, we looked for the possibility of a differential effect from U2AF1 mutation variants on these observations in PMF. Methods Study patients fulfilled the 2016 WHO criteria for the diagnosis of PMF (Blood. 2016;127:2391). Additional selection criteria included the availability of U2AF1 mutational status. Previously published methods (Leukemia 2014;28:431), including targeted next generation sequencing (Blood 2015 126:354), were used to screen for U2AF1 and other prognostically-relevant mutations. Statistical analyses considered clinical and laboratory parameters obtained at time of initial referral to the Mayo Clinic. Results Patient characteristics: U2AF1 mutational status was available for 457 patients and 72 (16%) harbored one of several mutation variants: these mutations affected residue Q157 in 44 (10%) patients, S34 in 24 (5%) and the remaining 1% displayed other variants. The 44 patients with U2AF1Q157 mutations included 23 with Q157P, 18 with Q157R and 3 with Q157-Y158insYE. The 24 patients with U2AF1S34 included 16 with S34F and 8 with S34Y. Only one patient harbored both Q157 and S34 mutations (Q157R, S34Y). Among all 457 study patients, median age was 63 years, 64% were males, dynamic international prognostic scoring system (DIPSS)-plus (JCO 2011;29:392) risk distributions were 13% low, 18% intermediate-1, 38% intermediate-2 and 32% high and driver mutation distributions were 54% JAK2, 22% CALR type 1/ type1-like, 4% CALR type 2/type 2-like, 7% MPL and 13% triple-negative. Cytogenetic studies were available in 449 patients: 39% abnormal and 10% unfavorable. All 457 patients were screened for ASXL1 mutations with 37% mutated, 450 for SRSF2 mutations with 15% mutated, 403 for SF3B1 with 8% mutated, 366 for IDH1/2 with 5% mutated and 369 for EZH2 with 4% mutated. Median follow-up was 4.4 years and during this period, 318 (70%) deaths and 53 (12%) leukemic transformations were documented. Phenotypic correlates of U2AF1 mutation variants: Because of the relatively small number of informative cases with specific mutations, we classified all patients into Q157 (n=44) and S34 (n=24) mutation variants and compared them with the 385 U2AF1 un-mutated cases. First, we confirmed our previous observations regarding the association between U2AF1 mutations in general and older age (p=0.0003), JAK2V617F (p<0.0001), ASXL1 mutations (p=0.0002), normal karyotype (p=0.03), hemoglobin <10 g/dL (p<0.0001) and platelet count <100 x 10(9)/L (p<0.0001); when the two U2AF1 mutation categories were analyzed separately, the corresponding p values for Q157 were 0.0005, 0.001, <0.0001, 0.04, <0.0001 and <0.0001 and for S34 were 0.12, 0.001, 0.41, 0.41, <0.0001 and 0.67. Phenotypic correlates of U2AF1 mutation variants: In univariate analysis, survival was adversely affected by U2AF1Q157 (p<0.0001; HR 2.2, 95% CI 1.6-3.1) but not by U2AF1S34 (p=0.8; HR 1.1, 95% CI 0.6-1.8) mutations (Figure 1a). Furthermore, the negative survival effect of U2AF1Q157 mutations was independent of anemia, thrombocytopenia, ASXL1, SRSF2, IDH1/2 and EZH2 mutations, as well as driver mutational status; multivariable analysis that included all molecular alterations identified U2AF1Q157 (HR 1.6, 95% CI 1.1-2.3), ASXL1 (HR 2.3, 95% CI 1.8-3.5), SRSF2 (HR 1.6, 95% CI 1.2-2.2) and absence of CALR type-1/like (HR 2.6, 95% CI 1.8-3.5) mutations as independent risk factors for survival. Finally, the survival effect of U2AF1Q157 mutations was independent of DIPSS-plus in patients with hemoglobin ≥10 g/dL (HR 2.6, 95% CI 1.3-5.3; p=0.007) (Figure 1c) but not in those with hemoglobin <10 g/dL (p=0.98) (Figure 1b). Conclusion Both U2AF1Q157 and U2AF1S34 mutation variants in PMF are associated with JAK2V617F and severe anemia whereas only the former is associated with ASXL1 mutations and thrombocytopenia. More importantly, U2AF1Q157, but not U2AF1S34, mutation variants in PMF are predictive of inferior survival, independent of other adverse mutations, and, in the absence of severe anemia, independent of DIPSS-plus. Disclosures No relevant conflicts of interest to declare.

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Low JAK2V617F Allele Burden in Primary Myelofibrosis, Compared to Either a Higher Allele Burden or Unmutated Status, Predicts Inferior Overall and Leukemia-Free Survival.

Blood ◽

10.1182/blood.v110.11.676.676 ◽

2007 ◽

Vol 110 (11) ◽

pp. 676-676

Author(s):

Ayalew Tefferi ◽

Terra L. Lasho ◽

Jocelin Huang ◽

Christy Finke ◽

Curtis A. Hanson ◽

...

Keyword(s):

Leukocyte Count ◽

Univariate Analysis ◽

Multivariable Analysis ◽

Primary Myelofibrosis ◽

Older Age ◽

World Health ◽

Lower Quartile ◽

Free Survival ◽

Allele Burden ◽

Mutational Status

Abstract Background : Two previous studies have reported significant but inconsistent associations between the presence of JAK2V617F in primary myelofibrosis (PMF) and older age at diagnosis, risk of thrombosis, higher leukocyte count, and inferior survival (Tefferi, et al. BJH2005;131:320, Campbell, et al. Blood2006;107:2098). The clinical relevance of V617F allele burden in PMF has not been previously studied. Methods : Diagnosis of PMF was based on the World Health Organization criteria and study eligibility included the availability of bone marrow-derived DNA that was collected either at time of diagnosis or within one year of diagnosis. Quantitative allele specific PCR was utilized to meaure V617F allele burden. Results I. V617F-positive vs. V617F-negative comparisons: A total of 199 patients (60% males; median age 61 years) were suitable for analysis of comparisons between mutation-positive and mutation-negative disease. The Dupriez prognostic scoring system (PSS) risk distributions were 61% low-risk, 31% intermediate-risk, and 8% high-risk. Hypercatabolic symptoms were present in 27% of the patients and ≥1% peripheral blood (PB) blasts in 37%. At a median follow-up of 23 months (range 0–266), 57 patients (29%) had died, 17 (9%) developed leukemic transformation (LT) and 10 (5%) experienced major thrombosis. V617F mutational frequency was 58%. Univariate analysis identified older age (p=0.0007), platelet count ≥ 100 x 109/L (p=0.05), and PB blast percentage < 3% (p=0.001) as being associated with a positive mutational status; all three variables sustained their significance during multivariable analysis. The presence of the mutation did not affect the incidence of thrombosis (p=0.78), overall survival (p=0.22) or leukemia-free survival (p=0.5). Results II. Clinical correlates of V617F allele burden: Quantitative measurement of V617F allele burden was performed in 129 patients that were divided into four groups: V617F-negative (n=53) and V617F-positive with mutant allele burden in the lower quartile (n=19), middle quartiles (n=38), or upper quartile (n=19) range (median and range of V617F allele burden ratio was 29% and 1% to 74%). Kaplan-Meier plots revealed significantly shortened overall (Figure; p = 0.0008) and leukemia-free (p = 0.01) survival for the lower quartile allele burden group; survival significance was sustained in a multivariable analysis that included the Dupriez PSS. Lower quartile allele burden was also associated with lower leukocyte count (p = 0.003) and presence of hypercatabolic symptoms (p=0.05). Thrombosis incidence was not affected by allele burden. Conclusions: In PMF, patients with a low V617F allele burden, compared to those with either undetectable (i.e. wild-type) or higher allele burden, display significantly shorter overall and leukemia-free survival. In contrast, the presence or absence of the mutation, by itself, does not result in distinct groups that differ significantly in terms of survival, LT, or incidence of thrombosis. These data suggest that a low V617F allele burden in PMF is a surrogate for the development of dominant V617F-negative subclones that are more likely to undergo LT. Figure Figure

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Circulating IL-2R, IL-8, IL-15 and CXCL10 Levels Are Independently Prognostic In Primary Myelofibrosis: A Comprehensive Cytokine Profiling Study

Blood ◽

10.1182/blood.v116.21.3068.3068 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3068-3068 ◽

Cited By ~ 1

Author(s):

Rakhee Vaidya ◽

Domenica Caramazza ◽

Christy Finke ◽

Terra Lasho ◽

Animesh Pardanani ◽

...

Keyword(s):

Prognostic Value ◽

Univariate Analysis ◽

Multivariable Analysis ◽

Elevated Serum ◽

Primary Myelofibrosis ◽

Serum Levels ◽

Cytokine Expression ◽

Risk Category ◽

Prognostic Relevance ◽

Cytokine Levels

Abstract Abstract 3068 Background: Abnormal cytokine expression accompanies the disease process in primary myelofibrosis (PMF) and the levels of proinflammatory cytokines have been shown to be down-regulated by JAK inhibitor therapy. The prognostic relevance of increased cytokine levels in PMF has not been systematically studied. The objectives of the current study were to describe the spectrum of abnormal cytokine expression in PMF and determine its prognostic relevance. Methods: A multiplex biometric sandwich immunoassay (Invitrogen multiplex assays, Invitrogen Corporation-Carlsbad CA, USA) was used for simultaneous analysis of 30 cytokine levels. Diluted plasma was mixed with fluorescently addressed microbeads bound with anti-cytokine antibodies. Biotin anticytokine secondary antibodies were then added and allowed to bind to cytokine-bead complexes. Total surface fluorescence for each bead was then measured using a Luminex (Luminex Corporation, Austin, TX, USA) fluorescent flow-based detection system. Results: Cytokine levels at diagnosis were analyzed for a total of 127 treatment naïve patients with PMF, who had stored sera at the time of diagnosis or first referral to the Mayo Clinic. The circulating levels of 30 cytokines in the multiplex assay were compared between PMF patients (n=127) and normal controls (n=31). Significant differences (p<0.05) were evident for 20 of the 30 cytokines: IL-1b, IL-1RA, IL-2R,IL-6, IL-8, IL-10, IL-12, IL-13, IL- 15, TNF-α, G-CSF, INF-α, INF-γ, MIP-1α, MIP-1β, HGF, CXCL10, MIG, MCP-1 and VEGF. On univariate analysis, increased levels of 9 of these 20 cytokines were associated with shortened survival (p<0.05): IL-1RA, IL-2R, IL-6, IL-8, IL-12, IL-15, MIP-1α, CXCL10 and MIG. On multivariable analysis, 4 of these 9 cytokines maintained their prognostic value for survival: IL-2R (p=0.0011), IL-8 (p<0.0001), IL-15 (p=0.0124) and CXCL10 (p=0.0031). The independent prognostic value of these 4 cytokines was sustained during additional multivariable analysis that included the Dynamic International Prognostic System Score and cytogenetic risk category. Next, we divided the 127 patients into three cytokine risk categories based on the serum levels of IL-2R, IL-8, IL-15 and CXCL10: none elevated, one or two elevated and three or four elevated. The respective median survivals were 69, 37 and 19 months (p=0.01; Figure 1) and such cytokine risk categorization was both DIPSS and cytogenetic risk independent; p values for multivariable analysis including cytokine, DIPSS, cytogenetic risk groups were 0.02, 0.0001 and 0.004, respectively. Conclusions: Elevated serum levels of IL-2R, IL-8, IL- 15 and CXCL10 independently predict shortened survival in PMF and such prognostication appears to be independent of DIPSS and cytogenetic risk category. The current study suggests clinical relevance of multiple cytokines in PMF that could be therapeutically targeted. Disclosures: No relevant conflicts of interest to declare.

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Mutations and Long-Term Outcome of 217 Young Patients with Essential Thrombocythemia or Early Primary Myelofibrosis

Blood ◽

10.1182/blood.v124.21.3190.3190 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3190-3190

Author(s):

Francesca Palandri ◽

Nicola Polverelli ◽

Roberto Latagliata ◽

Alessia Tieghi ◽

Emanuela Ottaviani ◽

...

Keyword(s):

Young Adults ◽

Triple Negative ◽

Univariate Analysis ◽

Primary Myelofibrosis ◽

Event Free Survival ◽

Abnormal Karyotype ◽

Term Outcome ◽

Long Term Outcome ◽

Free Survival ◽

Mutational Status

Abstract Introduction Young adults with Essential Thrombocythemia (ET) or early Primary Myelofibrosis (early-PMF) are a category of patients projected to a prolonged survival but also to an extended utilization of medical resources. Mutations, including those in the calreticulin (CALR) gene, have been reported to affect main clinical features and outcome in large cohorts of patients with Ph-negative MPNs. However, no data are available on mutational status and long-term outcome in young MPN patients. Methods A clinic-pathologic database of ET patients followed in 5 Italian Hematology Centers was created. A total of 217 WHO-diagnosed ET or early-PMF patients ≤ 40 years at diagnosis was retrieved from the general database of 2635 patients. All bone marrow biopsies were reviewed at local institution. Baseline clinical/molecular characteristics and outcome measures (thrombosis, hemorrhages, secondary MF and AL, second neoplasia, death, overall and event-free survival) were evaluated. JAK2V617F allele-burden was assessed in granulocyte DNA by using ipsogen JAK2 MutaQuant Kit (qPCR). CALR mutations were identified by next generation sequencing (NGS) approach on GS Junior (Roche-454 platform); MPL mutations were evaluated by using ipsogen MPLW515L/K MutaScreen Kit. Results Overall, 197 WHO-defined ET and 20 early-PMF (age range: 16-40, median 34) were included in the study. Mutational frequencies were 61% for JAK2, 25% for CALR, 1% for MPL and 13% for triple negative. Baseline clinical characteristics and use of antiplatelet/cytoreductive therapies were comparable in ET and early-PMF, although frequency of triple negative was higher in the early-PMF cohort. Compared to the JAK2 positive population, both CALR and triple-negative patients showed higher platelet count and lower hemoglobin and hematocrit levels (Table 1). Median follow-up was 10.2 years (range: 0.5-37.5). During follow-up, 19 (9,6%) ET and 3 (15%) early-PMF patients experienced a total of 31 thrombotic (arterial: 38%) and 12 hemorrhagic events, with an incidence rate of 0.91% and 0.39% patients/yr, respectively. The cumulative incidence of thrombosis was 0,14% and 0,24% at 15 and at 20 years, respectively. Overall, 10 patients (4,6%) and 1 (0,4%) patients evolved to MF and AL, respectively; 10 developed a second neoplasia. The cumulative incidence of disease progression into MF/AL was 0,03% and 0,13% at 15 and at 20 years, respectively. At last contact, 6 (2,7%) patients had died, at a median age of 61 years (20-71), for an overall survival of 98% at 15 years. Causes of death were related to the myeloproliferative neoplasm (disease evolution or thrombotic complications) in all patients but one. Event-free survival was similar in the ET/early-PMF cohorts considering both every event separately and all together. In univariate analysis, male sex (p=0.003), previous thrombosis (p=0.001), splenomegaly (p=0.037), JAK2V617F (p=0.019) were associated with increased thrombotic risk; in multivariate Cox analysis, only previous thrombosis and male sex remained significant (p=0.012). Baseline splenomegaly was the only predictive factor for subsequent hemorrhages (p=0.017). Abnormal karyotype was associated with secondary MF (p=0.013) and also with second neoplasia (p<0.001). Together with JAK2V617F positivity and leukocytosis >11x109/L, abnormal karyotype was also associated with worse survival in univariate analysis. However, in multivariate analysis only JAK2V617F mutation remained as negative predictor of survival (p=0.019). Also, multivariable analysis confirmed JAK2 mutation and splenomegaly as independent risk factors for cumulative events. Conclusions With the limitations due to the low number of early-PMF, the outcome of young adults with early-PMF and true ET seemed to be comparable. The correlation of abnormal karyotype with MF transformation and second neoplasia suggests the need for an accurate cytogenetic analysis at diagnosis. Mutational status did influence disease phenotype, in terms of baseline characteristics and prognosis. Indeed, JAK2 mutational status confirmed a negative prognostic role for thrombosis and survival, while event-free survival was significantly better in triple-negative patients. Notably, causes of death were mostly related to the hematological malignancy, pointing out the substantial impact that this generally indolent disease may acquire in young adults. Disclosures Latagliata: Novartis: Consultancy; Bristol Myers-Squibb: Consultancy; Celgene: Consultancy; Shire: Consultancy. Cavo:Janssen: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; BMS: Consultancy, Honoraria; Millenium: Consultancy, Honoraria; Onyx: Honoraria.

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Driver Mutations and Prognosis in 1118 Patients with Primary Myelofibrosis

Blood ◽

10.1182/blood.v126.23.2801.2801 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2801-2801 ◽

Cited By ~ 1

Author(s):

Ayalew Tefferi ◽

Paola Guglielmelli ◽

Terra L. Lasho ◽

Yoseph Elala ◽

Tiziana Fanelli ◽

...

Keyword(s):

Research Funding ◽

Triple Negative ◽

Multivariable Analysis ◽

Primary Myelofibrosis ◽

Driver Mutations ◽

Leukemic Transformation ◽

Advisory Committees ◽

University Of Florence

Abstract Background : In primary myelofibrosis (PMF), ̴ 88% of patients harbor JAK2, CALR or MPL, with respective mutational frequencies of approximately 60%, 22% and 6%; ̴ 12% are wild type for all three driver mutations and are labelled as being "triple negative" (Blood. 2014;124:2507). It is now well-established that CALR-mutated patients with PMF display significantly better survival, compared to all the other mutational categories; in addition, preliminary data have suggested inferior survival for "triple-negative" cases (Leukemia. 2014;28:1472; Blood. 2014;124:1062) and the possibility that the favorable impact of CALR mutations might be restricted to CALR type 1 or type 1-like variants (Blood. 2014;124:2465). In the current study, we sought to clarify the prognostic impact of driver mutations, and CALR variants, on overall (OS) and leukemia-free (LFS) survival, in a two-center study involving 1118 patients. Methods: A total of 1118 patients with PMF from the Mayo Clinic (n =722) and University of Florence, Italy (n =396) were included in the current study. Study patients were selected based on availability of mutation information. PMF diagnosis was according to World Health Organization criteria (Blood. 2009;114:937). Previously published methods were used for CALR, JAK2 and MPL mutation analyses and determination of CALR variants (Blood. 2014;124:2465). Kaplan-Meier survival analysis was considered from the date of first referral for the Mayo cohort and date of diagnosis for the Florence cohort. Leukemic transformation events replaced death as the uncensored variable during LFS analysis and Cox proportional hazard regression model was used for multivariable analysis. Results : Analysis was first conducted on the Mayo cohort of 722 patients (median age 64 years; 64% males). DIPSS-plus risk distributions were 14% low, 17% intermediate-1, 37% intermediate-2 and 33% high. All patients were annotated for JAK2/CALR/MPL mutations as well as CALR variants; 477 harbored JAK2, 139 CALR and 41 MPL mutations; 65 patients were triple-negative. The 139 CALR -mutated patients included type 1/type 1-like (n =115) and type 2/type 2-like (n =24). At a median follow-up time of 3.1 years, 439 (61%) deaths and 63 (8.7%) blast transformations were documented. In univariate analysis, survival in patients with CALR type 1/type 1-like mutations was significantly longer than every other mutational category: HR (95% CI) were for triple-negative 2.7 (1.8-4.0), JAK2 2.7 (2.0-3.7), CALR type 2/type 2-like 2.3 (1.3-4.2) and MPL 1.9 (1.1-3.1) (Figure 1); these differences were sustained during multivariable analysis that included ASXL1 mutations (n =480) and DIPSS-plus, and were also apparent in the Florence cohort of 396 cases that included 251 JAK2, 53 CALR type 1/type 1-like, 21 CALR type 2/type 2-like, 50 triple-negative and 21 MPL mutated cases (Figure 2). There was no difference in survival among the Mayo cohort across mutational categories not including CALR type 1/type 1-like variants (p=0.33). Because specific driver mutations in PMF differentially cluster with age and sex, multivariable analysis including these two parameters was also performed and confirmed the significant survival advantage of CALR type 1/type 1-like over triple-negative, JAK2 and CALR type 2/type 2-like mutated cases. Based on the above information, we divided driver mutational categories into "type 1/type 1-like" (median survival 10.3 years) and "all other mutational categories" (median survival 3.9 years; p<0.01). The difference in survival between these two groups remained significant (HR 2.1, 95% CI 1.5-2.9) during multivariable analysis that included both DIPSS-plus (P<0.01) and ASXL1 mutation (HR 1.8, 95% CI 1.4-2.2). LFS was similar between these two groups (p=0.4) but it was inferior in triple-negative cases compared to CALR type 1/type 1-like variants (HR 2.8, 95% CI 1.3-6.2), MPL (HR 4.6; 95% CI 1.04-20.4) and JAK2 (HR 2.5, 95% CI 1.3-4.8) but not CALR type 2/type 2-like variants (p=0.56). There was no difference in LFS among mutational categories not including triple-negative cases (p=0.33). Conclusions : In PMF, driver mutations might be classified into two prognostically distinct categories: "favorable" (type 1/type 1-like) and "unfavorable" (all other mutational categories). In addition, triple-negative cases might be at a higher risk of leukemic transformation. Disclosures Pardanani: Stemline: Research Funding. Vannucchi:Novartis: Other: Research Funding paid to institution (University of Florence), Research Funding; Shire: Speakers Bureau; Baxalta: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

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Molecular Correlates of Anemia in Primary Myelofibrosis

Blood ◽

10.1182/blood.v126.23.4068.4068 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4068-4068

Author(s):

Daniela Barraco ◽

Terra L. Lasho ◽

Kebede H. Begna ◽

Naseema Gangat ◽

Christy Finke ◽

...

Keyword(s):

Triple Negative ◽

Primary Myelofibrosis ◽

Hemoglobin Level ◽

Older Age ◽

Driver Mutation ◽

World Health ◽

Driver Mutations ◽

Severe Anemia

Abstract Background : Anemia is one of the most prominent symptoms in primary myelofibrosis (PMF) and is often associated with inferior quality of life and survival. Current drugs, including JAK inhibitors, are suboptimal in the treatment of PMF-associated anemia and better information on its pathogenesis is critical for the development of more effective drugs. In the current study of JAK2/CALR/MPL annotated patients with PMF, we examined its correlation with both "driver" and "non-driver mutations", as well as cytogenetic abnormalities, in order to gain better insight into its pathogenesis. Methods: Study patients were selected based on availability of "driver" mutation information. PMF diagnosis was according to World Health Organization criteria (Blood. 2009;114:937). Previously published methods were used for CALR, JAK2 and MPL mutation analyses and determination of CALR variants (Blood. 2014;124:2465). Considering their relatively high mutational frequency in PMF, subsets of patients were also screened for ASXL1, spliceosome component (SF3B1, U2AF1, SRSF2, ZRSR2) and TET2 mutations. Cytogenetic analysis and reporting was done according to the International System for Human Cytogenetic Nomenclature. Statistical analyses considered clinical and laboratory parameters obtained at time of first referral at the Mayo Clinic. Results : Analysis was conducted on 722 patients (median age 64 years; 64% males). DIPSS-plus risk distribution was 14% low, 17% intermediate-1, 37% intermediate-2 and 33% high. All patients were annotated for JAK2/CALR/MPL mutations as well as CALR variants; 477 harbored JAK2, 139 CALR and 41 MPL mutations; 65 patients were triple-negative. The 139 CALR -mutated patients included type 1/type 1-like (n =115) and type 2/type 2-like (n =24). Non-driver mutations screened included ASXL1 (n =480; mutated 38%), SRSF2 (n =474; mutated 14%), U2AF1 (n =457; mutated 16%), SF3B1 (n =328; mutated 8%), ZRSR2 (n =180; mutated 11%) and TET2 (n =180; mutated 18%). Karyotype was normal in 60%, favorable in 28% and unfavorable in 12%. Anemia was defined as being absent (normal sex-adjusted hemoglobin level; n =110; 15%), mild (hemoglobin level of ≥10 g/dL but below sex-adjusted normal value; n =263; 36%), moderate (hemoglobin level below 10 g/dL but not transfusion-dependent; n =108; 15%) and severe (transfusion-dependent anemia; n =241; 33%). Presence of at least mild anemia was associated with abnormal karyotype (p=0.006) with no difference between favorable and unfavorable abnormalities, U2AF1 (p=0.002), TET2 (p=0.02) and ASXL1 (p=0.04) mutations; other significant associations included male sex and older age. Presence of moderate to severe anemia was associated with U2AF1 (p<0.0001), SRSF2 (p=0.007) and driver mutations other than CALR type 1/type 1-like (p<0.0001). Presence of severe anemia was associated with U2AF1 (p<0.0001), SRSF2 (p=0.003) and non-CALR driver mutations (17% incidence in both types of CALR variants vs 51% in triple negative, 35% JAK2, 39% MPL mutated cases; p<0.0001). An association with older age but not gender was also noted for both moderate to severe and severe anemia (p<0.0001). During multivariable analysis, independent associations with moderate to severe anemia were confirmed for U2AF1 (p<0.0001), SRSF2 (p=0.007) and age (p=0.0001), but not driver mutation profile (p=0.30). A similar analysis for severe anemia also identified U2AF1, SRSF2 and age as being significantly relevant. Conclusions : The current study identifies older age and the spliceosomal mutations U2AF1 and SRSF2 as having strong and independent association with moderate to severe anemia in PMF. Targeting the spliceosome machinery or its mutant components offers a potential approach in the treatment of PMF-associated anemia. Disclosures Pardanani: Stemline: Research Funding.

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Prefibrotic Versus Overtly Fibrotic Primary Myelofibrosis: Clinical, Cytogenetic, Molecular and Prognostic Comparisons

Blood ◽

10.1182/blood.v128.22.4247.4247 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4247-4247 ◽

Cited By ~ 2

Author(s):

Mythri Mudireddy ◽

Sahrish Shah ◽

Terra L. Lasho ◽

Daniela Barraco ◽

Curtis A. Hanson ◽

...

Keyword(s):

Lower Incidence ◽

Scoring System ◽

Triple Negative ◽

Univariate Analysis ◽

Primary Myelofibrosis ◽

Prognostic Relevance ◽

Significant Difference ◽

Risk Distribution ◽

Grade 3

Abstract Background The 2016 revised World Health Organization (WHO) classification system distinguishes prefibrotic (pre-PMF) from overtly fibrotic (overt PMF) primary myelofibrosis, based on the respective absence or presence of grade ≥2 bone marrow (BM) reticulin fibrosis (Blood. 2016;127:2391). The main objective of the current study was to determine the prognostic relevance of this distinction and compare clinical and genetic features between the two entities. Methods Study patients fulfilled the 2016 WHO criteria for the diagnosis of pre-PMF or overt PMF (Blood. 2016;127:2391). The degree of BM reticulin fibrosis was based on "real life" BM reports from Mayo Clinic hematopathologists and often in accordance with the European consensus scoring system (Haematologica 2005;90:1128). Targeted next generation sequencing was used to screen for prognostically-relevant mutations (Blood 2015 126:354). Statistical analyses considered clinical and laboratory parameters obtained at time of BM examination that was graded for reticulin fibrosis. Results Patient characteristics: Analysis was conducted on 467 patients (median age 64 years; 62% males), including 63 with pre-PMF and 404 with overt PMF. 302 (65%) patients harbored JAK2 mutations, 90 (19%) CALR, 24 (5%) MPL and 51 (11%) were "triple-negative"; among the 90 CALR-mutated cases, 74 (82%) were classified as "type 1/type 1-like". Dynamic international prognostic scoring system (DIPSS)-plus risk distribution (JCO 2011;29:392) was 30% high, 38% intermediate-2, 16% intermediate-1 and 15% low; 29% displayed red cell transfusion-dependency, 29% constitutional symptoms, 70% palpable splenomegaly and 37% abnormal karyotype, including 13% with unfavorable karyotype. 308 patients were screened for ASXL1 mutations with 39% mutated, 305 for SRSF2 mutations with 16% mutated, 291 for U2AF1 with 18% mutated, 264 for SF3B1 with 6% mutated, 240 for EZH2 with 5% mutated and 118 for IDH1/2 with 7% mutated. BM reticulin fibrosis was reported as grade '0' in 5 (1%) patients, grade '1' in 58 (12%), grade '2' in 169 (36%) and grade '3' in 235 (50%). After a median follow up of 3 years, 273 (59%) deaths and 42 (9%) leukemic transformations were documented. Clinical, cytogenetic and molecular comparisons between pre-PMF vs overt PMF: Significant differences included higher hemoglobin level (p<0.0001), higher platelet count (p<0.0001), higher incidence of thrombocytosis (p<0.0001), lower circulating blast percentage (p=0.0002), lower incidence of constitutional symptoms (p=0.003), lower incidence of palpable splenomegaly and lower DIPSS-plus risk distribution (p=0.0004), in pre-PMF, compared to overt PMF. There were significantly more triple-negative patients with pre-PMF (22% vs 9% for overt PMF; p=0.02) but otherwise no significant difference in the distribution of ASXL1, SRSF2, U2AF1, SF3B1, EZH2 or IDH1/2 mutations or incidence of unfavorable karyotype. Survival analysis: In univariate analysis, all 8 variables included in DIPSS-plus were significantly associated with shortened survival (p<0.001 in all instances). Significant risk factors in univariate analysis also included overt PMF vs pre-PMF (p=0.002; HR 2.0, 95% CI 1.3-3.1), absence of CALR type 1/type 1-like (p<0.0001) and presence of ASXL1 (p<0.0001) or SRSF2 (p<0.0001) mutations. The significant difference in survival between pre-PMF and overt PMF was independent of DIPSS-plus (p=0.03), driver mutational status (p=0.001), ASXL1 (p=0.008) and SRSF2 (p=0.02) mutations; no significant difference in leukemia-free survival was noted (p=0.25). The survival difference between pre-PMF and overt PMF was most evident in high/intermediate-2 DIPSS-plus risk groups (Figure). Of note, we found no difference in survival when patients with grade '0' were compared to those with grade '1' reticulin fibrosis (p=0.96) and when those with grade '2' were compared with grade '3' (p=0.08). Conclusion The current study demonstrates the risk-adjusted prognostic relevance of the WHO distinction between pre-PMF and overt PMF. The two clinic-pathologic entities were otherwise similar in their spectrum of prognostically-relevant mutations or cytogenetic abnormalities, although pre-PMF clustered with thrombocythemic and triple-negative phenotype and overt PMF with adverse clinical features. Figure Figure. Disclosures No relevant conflicts of interest to declare.

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