ALBERT

Description: Bone marrow (BM) fibrosis is a key pathomorphologic feature of patients (pts) with primary myelofibrosis (PMF) and the fibrotic phases of essential thrombocythemia (post-ET MF) and polycythemia vera (post-PV MF). The degree of BM fibrosis appears to correlate with survival. Indeed worse survival has been associated with increased BM fibrosis. The BM stromal microenvironment is important in the pathogenesis of BM fibrosis. Cellular components (fibroblasts, macrophages, endothelial cells, adipocytes), structural fibrils (collagen, reticulin) and extracellular matrix components are all forming elements of the BM stroma. Increased stromal fibrosis has been linked to abnormalities in the number/ function of megakaryocytes and platelets in hematologic diseases. Several cytokines like Platelet Derived Growth Factor (PDGF) and Transforming Growth Factor-Beta (TGF-b) have been also linked to the pathophysiology of BM fibrosis. PDGF has been shown to increase fibroblast growth in megakaryocytes and platelets although increased PDGF did not correlate with increased production of either reticulin or collagenous fibrosis. Moreover, PMF pts have increased TGF-b levels in platelets, megakaryocytes, and monocytes. Nitric Oxide (NO) is a ubiquitous gas important in physiologic processes particularly vasodilatation. Dysregulation of NO levels has been implicated in pulmonary hypertension (PH), hemoglobinopathies, and cardiovascular diseases. In Peyronie’s disease, a localized fibrosis of the penile tunica albuginea, increased NO production by expression of iNOS decreases collagen deposition by neutralization of profibrotic reactive oxygen species and decreased myofibroblast formation. Aside from its role in maintaining normal vascular tone, NO also plays a role in fibroblast formation and collagen biosynthesis. We previously reported that ruxolitinib, a JAK1/2 inhibitor restores NO levels leading to improvement of PH in MF pts (Tabarroki et al., Leukemia 2014). We now hypothesize that plasma/serum NO level is a key regulator of BM fibrosis in MF and that ruxolitinib treatment (Tx) leads to improvement of BM fibrosis by NO modulation. Using a Sievers 280i NO analyzer we measured the plasma/serum NO level of a large cohort (n=75) of pts with myeloid and myeloproliferative neoplasms (MPN) [MDS, RARS/RCMD=8; MPN, ET=8, PV=8, MF=24, Mastocytosis=7; MDS/MPN, CMML=11, MDS/MPN-U, RARS-T=9]. Healthy subjects (n=10) were used as a control. MPN pts had low NO (nM) levels among the pts studied with the lowest level found in MF pts: MF=30.31±11.8, PV=39.0±16.1, ET=36±20.3, RARS=74.6±41.7 (P=.01), CMML=84.4±89.2 (P=.04), RCMD=163.4±103.8 (P

Description: Myelodysplastic syndromes (MDS) are a heterogeneous group of blood cancers characterized by bone marrow (BM) failure, peripheral blood cytopenias, dysplasia, chromosomal abnormalities and an increased risk for transformation to acute myeloid leukemia (AML). Patients (pts) with higher risk disease are primarily treated with pharmacologic treatments like hypomethylating therapy (HMT) (5-azacytidine and decitabine). 5-azacytidine (AZA) and decitabine (DAC) can result in overall response rates of 36% with a median duration of response of 15 months and 17-21% with a median duration of response of 10 months, respectively. Pts refractory to HMT have poor outcomes with a median overall survival of ∼4 months. Spliceosome gene mutations are frequently found in certain subtypes of MDS specifically SF3B1 (∼28%), U2AF1 (6-12%) and SRSF2 (6-12%). The prognostic value of spliceosome mutations in different MDS subtypes has been largely investigated while the impact of these mutations on treatment response is still unknown. We aim to investigate the frequency of three commonly mutated spliceosome genes (SF3B1, U2AF1, and SRSF2) in pts who failed HMT in order to define mutational frequency and evaluate the feasibility of targeted therapy with next generation spliceosome inhibitors. We screened a cohort of 120 pts (MDS, 70; MDS/MPN, 33; MDS/sAML, 17; median age: 69; male/female: 85/35) that underwent HMT (AZA: 58; DAC: 21; AZA/DAC: 7; AZA/REV: 25; DAC/REV: 4; AZA/DAC/REV: 5). Forty-eight percent of pts failed HMT therapy as refractory or relapse. We performed Sanger sequencing on BM/peripheral blood DNA for known pathways involved in MDS pathogenesis including methylation (TET2, DNMT3A, IDH1/2), histone (ASXL1, UTX, EZH2), signaling (CBL, N/KRAS), transcription (RUNX1, TP53, JAK2), and RNA splicing (SF3B1, U2AF1, SRSF2). Data analysis was available for 90 pts. We detected a total of 131 mutations in different pathways. In total, spliceosome mutations were observed in 28/90 (31%) of pts. When we analyzed the presence of the mutations in relation to the rate of response, we found that pts who failed HMT have frequent spliceosome mutations: 17/58 (29%). We have reported that molecular mutations in TET2 and DNMT3A can predict response to treatment to HMT (Traina F, Blood (ASH Annual Meeting Abstracts), Nov 2011; 118: 461). Indeed, the frequency of mutations in methylation genes was lower in the group of pts who failed HMT (11/58; 18.9%) compared to pts who achieved hematological response (11/32; 34%). Spliceosome inhibitors have been proposed for targetted therapy in MDS. The presence of spliceosome mutations in pts who failed HMT can open a new era of investigation leading to the possibility of using spliceosome inhibitors in pts who fail conventional therapy. We performed RNA-sequencing analysis on BM cells of pts who failed HMT compared to pts who achieved hematological response (n=2 vs 2) in order to define any specific gene signature explaining the differences in response to HMT. We performed differential gene expression testing on 11,459 expressed genes. In total, 158 genes were differentially expressed at FDR 〈 .2 in responders compared to not responders. We identified several interesting genes involved in tumorigenesis and epigenetic regulation such as YPEL3, and ST14, which were up-regulated in responders vs not responders (FC: 4 and 7.5; P

Description: Isochromosome 17q [i(17q)], a poor prognostic cytogenetic abnormality is a product of the breakage or inappropriate division of the pericentromere leading to the duplication of the long and loss of the short arm of chromosome 17. The region of the breakpoints maps at 17p11, a region encompassing a key tumor suppressor gene: TP53. I(17q) are detected in myelodysplastic/ myeloproliferative neoplasms (MDS/ MPN), chronic myeloid leukemia (CML), and acute myeloid leukemia (AML). This abnormality can occur as a sole structural abnormality or in combination with other chromosomal defects. The presence of i(17q) is associated with poor therapeutic response, disease progression, and an unfavorable clinical outcome. Elucidation of the molecular architecture of patients (pts) carrying i(17q) may lead to better understanding of disease biology and development of novel compounds that can target this disease. We selected 11 pts with i(17q) to characterize their genomic differences. We applied whole exome sequencing (WES) in order to define latent molecular defects explaining the clinical phenotype of this disease. The index case was a male MDS/MPN pt with isolated i(17q), 27% RS, hypercellular bone marrow (BM), mild splenomegaly, and atypical megakaryocytes. The pt developed 7% BM blasts without clinical response to growth factors. Molecularly this pt was a wild type SF3B1, a gene frequently mutated in RARS-T and associated with lower transformation rate to leukemia, better survival, and good/intermediate risk cytogenetic abnormalities. WES was performed on 2 ug of total DNA extracted from BM cells. Non-clonal CD3+ cells were used as source of germ-line control. Twenty-millions reads were run on an Illumina HiSeq2000 sequencer. Using a stringent bio-informatic algorithm developed in house, all variants were filtered based on a variation score (〉=30) and a coverage (30X) and the tumor nucleotide variation analysis was performed for each pair (tumor vs. germ-line), where only the variants unique to the tumor were retained. Variants were ultimately filtered in order to exclude SNPs by an in-house annotation and importing the hg19 SNP135. We detected 65 unique candidate genes. Four genes were confirmed to be somatic: 3 were novel: ZFP42 (4q35.2), P4HTM (3p21.31), and VPRBP (3p21.2) and 1 includes the newly discovered SETBP1 (18q12.3) gene. Three variants detected on the chromosome 17 had a wild type configuration. The subsequently genotyped all the pts (MDS/MPN/-U 3; AML 4; RCMD 1; CML 1; RAEB-1 2; mean age: 68 years; male/female: 8/3; i(17q)/other abnormalities:3/8) for the above genes and for a panel of genes known to be mutated in MDS/MPN and other diseases in order to find any genetic association explaining the disase phenotype. We applied Sanger sequencing to DNA derived from BM/peripheral blood cells (BM/PB:7/4) for the following genes and respective exons: TP53 (all exons), SF3B1 (13-16), SRSF2 (1-2), U2AF1 (2 and 6), TET2 (all exons), DNMT3A (18-23), IDH1/2 (4), CBL (8-9), N/KRAS (1-2), ASXL1 (12), JAK2 (12 and 14), EZH2 (16, 18 and 19), MPL (exon 10), BCAS3 (12, 15 and 16), FLT3 (11 and 17), and CSF3R (13,14, and 17). In total, we found 16 heterozygous missense mutations and 1 tandem duplication. We found somatic mutations in ZFP42, P4HTM, and VPRBP in 1 pt. The index case reported a mutation in SETBP1 and SRSF2. SF3B1 was detected as a sole abnormality in 1 patient. Of note, the patient with SF3B1 mutation (K700E) had 50% RS and achieved a complete hematologic remission after decitabine therapy. The most frequent mutations were found in SETBP1 and SRSF2. SETBP1 was found to be mutated in 4/11 (36.3%) pts (D868N, I871T, and G870S was common in 2 pts) while SRSF2 mutations (P95H/R) were found in 3/11 (27.2%) pts. Three pts showed concomitant SRSF2 and SETBP1 mutations. NRAS (G12D) was mutated in 1 pt and associated with SRSF2 and SETBP1 mutations. One pt showed mutations in TET2, JAK2, and TP53. Of note, this pt did not respond to treatment. One pt with MDS/MPN showed a mutation in CSF3R (Q741X), a novel gene discovered in chronic neutrophilic leukemia and atypical CML. The pt also has monosomy 7 and i(17q) abnormality. FLT3-ITD was found in 1 pt. As of last follow-up, only 2 pts remain alive. In sum, we found that poor risk molecular mutations in SRSF2 and SETBP1 are frequently found in i(17q) myeloid malignancies and may be the drivers of poor outcomes in this disease. Disclosures: No relevant conflicts of interest to declare.

Description: Pharmacologic therapies that target the JAK-STAT pathway are clinically used to alleviate splenomegaly and disease-related constitutional symptoms in MF. However, it is clear that some patients develop intolerance or resistant to this therapy. Furthermore, there are MF related complications especially cytopenias that are not alleviated by these therapies. Therefore, alternative and complementarytherapies are warranted in the management of MF. We hypothesized that other pathways downstream of the JAK-STAT signaling pathway can play a role in the pathophysiology of MF. We used whole exome (WES) and RNA sequencing technologies to interrogate new molecular markers and pathways which can serve as novel targets for this disease. In 4 MF patients [JAK2 mutant (MUT) =2, and wild type (WT) =2], WES was performed using the Illumina platform. All of the variants were filtered based on PHRED score (〉=30) with coverage was set at 30X. Analysis of data in JAK2/MPL WT patients demonstrated the presence of 263 candidate genes. After clarifying the status of tumor nucleotide variants in each gene compared to germline (CD3+) fraction, 7 genes (RBL1, ADSS, ZNF717,MUC4, TUBB4Q and CDC25A) were selected for further somatic confirmation by direct sequencing. Among these genes, only alteration in CDC25A, a regulator of cyclinE/cdk2 (cyclin-dependent kinase-2) and cyclinA/cdk2 kinase, was confirmed to be somatic. This genetic change was previously reported as somatic by WES in lung cancer although not confirmed by direct sequencing (Bartkova et al, Nature, 2005, Apr 14; 434 (7035):864-70). Based on these observations and since CDC25A acts as a downstream effector of JAK-STAT signaling, we hypothesized that, CDC25A phosphatase, may be a driver in MF pathogenesis. The transcriptome of two patients, one MUT and one WT for JAK2 was then analyzed. RNA was isolated from bone marrow (BM) cells of healthy individuals (HI) (N=3). cDNA was made from 1.5-3 ug of RNA and fragmented for library preparation. RNA-sequencing was performed on 20 million sequence reads. Paired-end 90 base pair reads were generated on an Illumina HiSeq2000 sequencer and aligned to the human genome 19. RNA-splicing patterns were analyzed by a bioinformatics algorithm and gene expression analysis was carried out using GSEA (Visconte V; Blood. 2012). By using FDR80%) while JAK2 MUT samples had only a few positive megakaryocytes (

Description: Aplastic Anemia (AA) is a rare bone marrow failure disorder characterized by pancytopenia, and an empty bone marrow. The disease can develop from unknown causes (idiopathic) or can be secondary to drugs, toxins, chemotherapy (acquired). Hematopoietic bone marrow transplant is a potential cure for idiopathic AA patients. Pharmacologic therapies remain the foremost therapy for patients who lack suitable donors or ineligible for bone marrow transplant. Antithymocyte globulin (ATG) is a first line treatment for these patients. However, relapsed and refractory cases of AA can occur even after ATG treatment. Patients with relapsed/ refractory AA may benefit from alternative immunosuppressive therapies. Alefacept is a novel immunosuppressive agent that targets the CD2-LFA3 pathway important in various T cell functions especially T cell activation. The occurrence of relapsed/ refractory cases of AA coupled with the side effect profile of ATG prompted us to test alefacept in refractory AA. This Phase I/II study was fully approved by the Institutional Review Board of the Cleveland Clinic and conducted in patients with relapsed/ refractory AA. This trial was registered under ClinicalTrial.Gov Identifier Number: NCT01267643. A total of four patients were successfully enrolled in this trial. All four patients had refractory AA. Antecedent treatment for three patients was immunosuppressive therapy: ATG in one case, cyclosporine in one, and both plus daclizumab in one case. All patients are female. Patient ages at the beginning of the study were 39, 57, 83, and 90 years. Three of the four patients were ECOG performance status 1 and one patient was ECOG 2. Three patients received dose level 1 (7.5 mg/ week) while one patient was treated at dose level 2 (10 mg/week). All patients received once weekly treatments for a total of 12 weeks. All 4 patients have been followed for 15, 13, 12, and 11 months, respectively. None of the patients had a PNH clone at presentation. Blood parameters at the beginning of the alefacept treatment indicated that two patients had three cytopenias (Hgb

Description: Abstract 312 Prognosis in myelodysplastic syndromes (MDS) is heavily influenced by cytogenetics. Trisomy 8 (+8) is reported in 15–20% of MDS patients (pts) and is one of the most commonly identified karyotypes in this disease. Sole +8 is an intermediate-risk karyotype in MDS by the International Prognostic Scoring System (IPSS). However, pts with +8 myeloid malignancies exhibit wide clinical heterogeneity. In chronic myelomonocytic leukemia (CMML), +8 is considered high-risk, while in MDS functional data suggests an “immunopathologic” cause that is responsive to immunosuppressive agents and confers a good prognosis. Single nucleotide polymorphism array (SNP-A) and molecular technologies (next generation sequencing) have led to further refinement of prognosis in MDS, and subsequent discovery of molecular mutations with distinct effects on outcomes. We hypothesized that the differential outcomes noted in +8 MDS are primarily influenced by both clinicomorphologic features and the acquisition of new cytogenetic (isolated, +1, ≥2) and molecular defects. To further characterize the clinical and molecular behavior of +8 myeloid neoplasms, we analyzed 68 pts seen at the Cleveland Clinic with a +8 clone. Hematologic, bone marrow (BM), cytogenetic (metaphase cytogenetic [MC]/SNP-A) and survival data were collected. Survival comparisons were made by Kaplan-Meier analyses. Cox-proportional hazard ratio was used to determine factors predictive of outcomes. Response was evaluated per International Working Group 2006 criteria. Most (69%) pts were male; median age 69 years (38–89), and median follow-up 15 months. 69% (47/68) had MDS, 10% (7/68) MDS/MPN, 3% (2/68) MPN and 18% (12/68) AML. 41% of pts had an isolated +8 abnormality (+8 (i)), 16% had one additional abnormality (+8plus1), and 43% had ≥2 additional abnormalities defined as +8complex. By IPSS, Int-1=34%, Int-2=25%, high=42%. SNP-A data were available in 51% of the cases and detected new lesions in 60% of them (gains[46%], losses[43%], UPD[23%]). Clinically, pts with +8complex had higher median peripheral blood blasts (PB) compared to +8plus1 and +8(i) (3.5 vs 0 vs 0%,p=.04). By treatment, pts received high intensity (BMT±high dose chemo=35%), low intensity (hypomethylating agents [HMA]± lenalidomide=37%) or supportive therapies=28%). Overall response rate was 47%, with 14% CR. By cytogenetic grouping, +8complex had lower response rates compared to +8 with additional karyotype (30 vs 60 vs 52%; p=.06). Median overall survival (OS) was 15 months, and median event free survival (EFS) was 8 months, with worse OS noted in +8 complex compared to +8 plus1 and +8(i) (OS=11 vs 22 vs 29 months, p=.02; EFS=5 vs 10 vs 12 months; p=.04). To investigate the biologic rationale of these observations, we performing direct sequencing for poor prognostic genes in myeloid malignancies, such as ASXL1, IDH1/2, EZH2, K/NRAS, CBL and TP53 and for predictors of good outcomes/response like SF3B1/TET2. Molecular mutations were identified in 9/24 (38%) pts, with mutational frequencies within +8(i) (12 pts) of TET2 (42%), ASXL1 (42%), K-/NRAS (17%), SF3B1 (17%), and TP53 (0%). None of these mutations were detected in the +8plus1 or +8complex cohorts except for TP53 in one +8complex pt. No IDH1/2/EZH2/CBL mutations were found in the entire +8 cohort. Interestingly, mutations in TET2 conferred a better OS (88 vs 12 mos; p=.01). In +8 myeloid malignancies, ASXL1 mutations did not impact OS. We are currently performing whole exome sequencing and other immunogenetic studies in +8 pts to help identify factors that contribute to these group outcomes. To further define factors predictive of worse outcomes in +8 pts, univariate and multivariate analyses were performed and a predictive model of OS was designed. Using a simple scoring system, one point each was assigned to LDH ≥240, platelets 5%, and 2 points to an ANC 2], median OS=4.6 months; p

Description: Abstract 1261 LGL leukemia is a rare bone marrow failure disorder characterized by a clonal expansion of terminally differentiated T- or NK-cells with large cytoplasmic granules. Cytopenias of one or multiple lineages are the dominant phenotype, though lymphocytosis without cytopenias can also be present. Goals of therapy are minimizing cytopenias. Currently used immunosuppressive and chemotherapeutic agents have produced variable clinical responses. Predictors of response to therapy and overall outcomes have not been well studied. We reviewed 92 LGL patients (pts, T-LGL=79, NK-LGL=13) seen at Cleveland Clinic from January 2000 to July 2012 treated with various therapeutic agents. Overall (OS) and Progression-Free (PFS) Survival and Time to Next Treatment (TTNT) were estimated using the Kaplan-Meier method. The first three treatments for LGL pts were evaluated with TTNT; observation was not considered a treatment for this analysis. Risk factors for PFS and OS after initial treatment (including those who were never treated) were identified using Cox proportional hazard analysis. Clinical factors evaluated at time of diagnosis include age, sex, neutropenia (absolute neutrophil count ≤1000 per μL), anemia (hemoglobin ≤10gm/dL or transfusion requirement), lymphocytosis (absolute lymphocyte count 〉4000 per μL), lymphopenia (absolute lymphocyte count ≤1000 per μL), thrombocytopenia (platelet count ≤100 per μL), transfusion dependence (any red-cell transfusion requirement around time of diagnosis), history of B-cell dyscrasia and history of an autoimmune disease. Clinicopathologic risk factors included type of LGL leukemia (T- vs. NK-cell), detection of a monoclonal protein, number of Vβ clones measured by flow cytometry, and T-cell clonality by T-cell receptor (TCR)-γ rearrangement. P values of ≤0.05 were considered statistically significant. The median age of the cohort was 63 years (range: 16–85). 61% were male. Treatments (n=129) included cyclophosphamide (n=31), cyclosporine (n=33), methotrexate (n=25), alemtuzumab (n=12), chemotherapy (n=7), others (n=21), and supportive care or observation (n=28). Median TTNT was 18 months (range

Description: Ruxolitinib is the only JAK 1/2 inhibitor approved by the FDA for the treatment of myelofibrosis (MF). It has been established that ruxolitinib helps improve disease-related constitutional symptoms and splenomegaly. However, studies have shown that ruxolitinib affects several cytokines (IL1, IL6, and TNF-α) and other immune processes (dendritic cells function and T-cell response) and has been linked to increased incidence of opportunistic and non-opportunistic infections. Here we report our experience at the Cleveland Clinic. A total of 50 patients (pts) with MF treated with ruxolitinib were included. The median age of the cohort was 68 years (range: 41-89), 28 of them were males and 22 were females. According to the Dynamic International Prognostic Scoring System (DIPSS), 5 pts had high risk, 23 had intermediate-2 risk, 21 had intermediate-1 risk and 1 had low risk disease. Of these pts, 18 developed infections during their treatment course. Of these infections, 12 were CTCAEv4.0 grade 1-2 and 6 were grade 3-4. Median age of the group was 66 years-old ranging between 50 and 83. Males=9 and females =9. The group was risk-stratified with DIPSS into high risk (N=3), intermediate-2 risk (N=7) and intermediate-1 risk (N=8).The infection started several months after initiation of JAK inhibitor treatment ranging between 2 weeks to 22 months (median of 8 months). Of note, 10 pts had episodes of infections prior to starting ruxolitinib (pneumonia N=5, cellulitis N=3, oral herpes N=2, UTI N=2, genital herpes N=1, Clostiridium difficile diarrhea N=1, viral diarrhea N=1, neutropenic fever N=1, spontaneous bacterial peritonitis N=1 and psoas muscle abscess N=1) . None of the patients had an active infection at the time of starting ruxolitinib. The median total dose given to the pts who developed grade1-2 infection was 20 mg daily, and for those who had grade 3-4 infection it was 15 mg daily. A variety of infections have been reported including pneumonia (N=4), cellulitisfolliculitis (N=4), Clostridium Difficile diarrhea (N=2), URI (N=1), neutropenic fever (N=1), MSSA bacteremia (N=1), herpes zoster activation (N=2), spontaneous bacterial peritonitis (N=1), perineal abscess (N=1) and one pt had a gluteal abscess after a bone marrow biopsy. Most of these infections resolved using oral or topical antibiotics (N=12). However, 6 pts required hospital admissions, and 5 of them required intravenous antibiotics. One of them required admission to the intensive care unit and two others required surgical interventions. Duration of treatment ranged between 1 to 8 weeks (median 2 weeks). Ruxolitinib had to be discontinued due to the severity of the infection in 2 pts, while the others either had a dose reduction or no dose alteration. Two pts required prophylactic antibiotics; one had recurrent SBP despite antimicrobial prophylaxis, while another pt required acyclovir prophylaxis while receiving glucocorticoids with ruxolitinib with no reactivation of Zoster infection. Predisposing factors for infections included a procedure (BMBx N=1), the concurrent use of other immunosuppressive drugs (steroids N=3, other agents N=3) and the prior use of systemic antibiotics in the pts who had C Diff infections (N=2). Only 2 pts had subsequent infections, one had oral herpes and the other had candida esophagitis which required hospitalization and treatment with IV antifungal drugs while on high dose steroids (dexamethasone 4 mg PO twice daily) for immune thrombocytopenia at the time of infection. Though 5 pts had already died at the time of the chart review, none of them died of infectious complications. In summary, infections can occur in patients treated with ruxolitinib but are generally mild. Most infections resolve after an adequate course of oral antimicrobial therapy suggesting that prophylactic antimicrobial agents may not be necessary or cost-effective in the vast majority of MF pts treated with ruxolitinib. Disclosures No relevant conflicts of interest to declare.

Description: Background: Sideroblastic anemia (SA) can present as congenital SA (CSA), acquired clonal SA, and acquired reversible SA. Patients (pts) with SA have anemia and ring sideroblasts (RS). Acquired clonal SA is often linked to myelodysplastic syndromes (MDS) or myelodysplastic/ myeloproliferative neoplasms (MDS/MPN). Clinico-pathologic overlap features, unmet morphologic and/or cytogenetic criteria complicate the diagnosis of SA leading to delayed therapies. Currently the diagnosis of SA is based on bone marrow (BM) examination and routine blood tests. There is a need to find easily testable biomarkers that can lead to faster diagnosis of clonal and non-clonal SA. Somatic mutation in splicing factor 3b, subunit 1 (SF3B1) are frequent in MDS-RS and MDS/MPN-RS and have been closely associated with RS. Objective: SF3B1 mutations can be a useful diagnostic biomarker for pts with acquired clonal SA who present with cytopenias and/or minimal morphologic changes suspicious of MDS and MDS/MPN but not sufficient to make a definitive diagnosis. Patients and Methods: Six pts with SA at presentation and seen at Cleveland Clinic were included in this study. The median age was 38 years (range, 6-75). Blood tests and BM biopsy showed persistent anemia [Hgb, 10.5 g/dL (range, 8.8-13)], RS [numerous (3 pts), 15% (1 pt), rare (1 pt) and 〉15% (2 pts)], 3/6 pts had minimal erythrodysplasia with 1 pt having a mild megakaryocytic dysplasia, 3 pts had hypercellular (60-90%), 2 pts had normocellular (50%, 80%) and 1 pt had hypocellular BM (30%) for age, and 〈 5% BM (2%=2 pts; 1%=1 pt; 3%=1 pt). Two pts had PLT count 〉 400 k/uL, 3 pts had 〉 100 k/uL, and 1pt

Description: Abstract 1701 Patients with features of MDS and MDS/MPN who do not fulfill diagnostic criteria for a specific subtype of MDS and MDS/MPN are categorized by the WHO 2008 diagnostic criteria as MDS-U and MDS/MPN-U. MDS includes RCUD, RCMD, RARS, RAEB-1, RAEB-2, MDS-U and 5q- syndrome while MDS/MPN includes CMML, JMML, atypical CML and MDS/MPN-U. The natural history of patients who belong to these disease subtypes are hetergeneous. Although included in currently accepted prognostic scoring schemes like the International Prognostic Scoring System (IPSS) in MDS, Revised IPSS, and MD Anderson prognostic scoring schemes, they represent a minority of patients in the cohort. Within MDS/MPN cases, the clinical heterogeneity of diseases that belong to this group has been recognized and has led to the development of the MD Anderson prognostic Scoring System for CMML. Similarly, a prognostic scoring system for JMML has also been devised to help in risk stratification and treatment decisions. However, there are no prognostic scoring systems for unclassified cases of MDS and MDS/MPN. Clinically, we observe stark differences in treatment responses and clinical outcomes between MDS/MPN-U and other MDS/MPN-subtypes, and MDS-U with other subtypes of MDS. In total, we studied 92 patients with unclassifiable cases seen at the Cleveland Clinic, including MDS/MPN-U (n=52 [57%]) and MDS-U (n=40 [43%]). Hematologic, bone marrow (BM), cytogenetic (metaphase cytogenetic [MC]/SNP-A) and survival data were collected. Survival comparisons were made by Kaplan-Meier analyses. Cox-proportional hazard ratio was used to determine factors predictive of outcomes. A p-value of ≤0.05 was considered statistically significant. In this cohort, median age at diagnosis was 69 years (20–88), 65% (60/92) were male, and 35% (32/92) were female. Median follow-up was 21 months. Median absolute neutrophil count (ANC) was 2.69k/uL (0–87), peripheral blood (PB) blasts 0% (0–70%), hemoglobin 9.6g/dL (5–15), and LDH 260 U/L (105–2113). SNP-A karyotyping was completed for 65 patients, and new cytogenetic mutations were detected in 72% (47/65): (gains [64%], losses [57%], UPDs [25%]). In 52% (49/92) of patients, we sequenced molecular mutations that typically confer poor prognosis in myeloid neoplasms, such as ASXL1, IDH1/2, EZH2, K/NRAS, CBL and TP53. This sequencing revealed a mutational frequency of 18% (9/49) in TET2, 14% (7/49) in ASXL1, 6% (3/49) in EZH2 exons 18–19, 2% (1/49) in CBL, 2% (1/49) in NRAS, and 4% (2/49) in TP53. No mutations were found in IDH1/2 and KRAS. In univariate analysis of clinciopathologic factors, the following factors were found to be associated with overall survival: ANC (≥8.5 vs