Role of a cyclopentadienyl ligand in a heteroleptic alkoxide precursor in atomic layer deposition.

Alkoxide precursors have been highlighted for depositing carbon-free films, but their use in Atomic Layer Deposition (ALD) often exhibits a non-saturated growth. This indicates no self-limiting growth due to the chain reaction of hydrolysis or ligand decomposition caused by ß-hydride elimination. In the previous study, we demonstrated that self-limiting growth of ALD can be achieved using our newly developed precursor, hafnium cyclopentadienyl tris(N-ethoxy-2,2-dimethyl propanamido) [HfCp(edpa)3]. To elucidate the growth mechanism and the role of cyclopentadienyl (Cp) ligand in a heteroleptic alkoxide precursor, herein, we compare homoleptic and heteroleptic Hf precursors consisting of N-ethoxy-2,2-dimethyl propanamido (edpa) ligands with and without cyclopentadienyl ligand-hafnium tetrakis(N-ethoxy-2,2-dimethyl propanamido) [Hf(edpa)4] and HfCp(edpa)3. We also investigate the role of a Cp ligand in growth characteristics. By substituting an alkoxide ligand with a Cp ligand, we could modify the surface reaction during ALD, preventing undesired reactions. The last remaining edpa after Hf(edpa)4 adsorption can undergo a hydride elimination reaction, resulting in surface O-H generation. In contrast, Cp remains after the HfCp(edpa)3 adsorption. Accordingly, we observe proper ALD growth with self-limiting properties. Thus, a comparative study of different ligands of the precursors can provide critical clues to the design of alkoxide precursors for obtaining typical ALD growth with a saturation behavior.

Reducing contact resistance of MoS2-based field effect transistors through uniform interlayer insertion via atomic layer deposition.

Molybdenum disulfide (MoS2), a semiconducting two-dimensional layered transition metal dichalcogenide (2D TMDC), with attractive properties enables the opening of a new electronics era beyond Si. However, the notoriously high contact resistance (RC) regardless of the electrode metal has been a major challenge in the practical applications of MoS2-based electronics. Moreover, it is difficult to lower RC because the conventional doping technique is unsuitable for MoS2 due to its ultrathin nature. Therefore, the metal-insulator-semiconductor (MIS) architecture has been proposed as a method to fabricate a reliable and stable contact with low RC. Herein, we introduce a strategy to fabricate MIS contact based on atomic layer deposition (ALD) to dramatically reduce the RC of single-layer MoS2 field effect transistors (FETs). We utilize ALD Al2O3 as an interlayer for the MIS contact of bottom-gated MoS2 FETs. Based on the Langmuir isotherm, the uniformity of ALD Al2O3 films on MoS2 can be increased by modulating the precursor injection pressures even at low temperatures of 150 °C. We discovered, for the first time, that film uniformity critically affects RC without altering the film thickness. Additionally, we can add functionality to the uniform interlayer by adopting isopropyl alcohol (IPA) as an oxidant. Tunneling resistance across the MIS contact is lowered by n-type doping of MoS2 induced by IPA as the oxidant in the ALD process. Through a highly uniform interlayer combined with strong doping, the contact resistance is improved by more than two orders of magnitude compared to that of other MoS2 FETs fabricated in this study.

Cytogenetic profiles of 2806 patients with acute myeloid leukemia-a retrospective multicenter nationwide study.

The cytogenetic and molecular data is recognized as the most valuable prognostic factor in acute myeloid leukemia (AML). Our aim was to systemically analyze the cytogenetics of Korean AML patients and to compare the cytogenetic profiles of various races to identify possible geographic heterogeneity. We retrospectively reviewed medical records of 2806 AML patients diagnosed at 11 tertiary teaching hospitals in Korea between January 2007 and December 2011. The most common recurrent chromosomal abnormality was t(8;21) (8.8 %, 238/2717), but t(15;17) showed an almost same number (8.6 %,235/2717). Among de novo AML, the most frequent aberrations were t(15;17), observed in 229 (10.7 %). The most common French-American-British (FAB) classification type was M2 (32.2 %), and recurrent cytogenetic abnormalities correlated with the FAB subtypes. Among 283 secondary AML cases, myelodysplastic syndrome was the most common predisposing factor. About 67.1 % of the secondary AML cases were associated with chromosomal aberrations, and chromosome 7 abnormalities (n = 45, 15.9 %) were most common. The incidence of FLT3 internal tandem duplication mutation was relatively low at 15 %. Our study reports certain similarities and differences in comparison to previous reports. Such discrepancies call for extensive epidemiological studies to clarify the role of genetic as well as geographic heterogeneity in the pathogenesis of AML.

Lotus japonicus SUNERGOS1 encodes a predicted subunit A of a DNA topoisomerase VI that is required for nodule differentiation and accommodation of rhizobial infection.

A symbiotic mutant of Lotus japonicus, called sunergos1-1 (suner1-1), originated from a har1-1 suppressor screen. suner1-1 supports epidermal infection by Mesorhizobium loti and initiates cell divisions for organogenesis of nodule primordia. However, these processes appear to be temporarily stalled early during symbiotic interaction, leading to a low nodule number phenotype. This defect is ephemeral and near wild-type nodule numbers are reached by suner1-1 at a later point after infection. Using an approach that combined map-based cloning and next-generation sequencing we have identified the causative mutation and show that the suner1-1 phenotype is determined by a weak recessive allele, with the corresponding wild-type SUNER1 locus encoding a predicted subunit A of a DNA topoisomerase VI. Our data suggest that at least one function of SUNER1 during symbiosis is to participate in endoreduplication, which is an essential step during normal differentiation of functional, nitrogen-fixing nodules.

Azacitidine Pre-Treatment Followed by Reduced-Intensity Stem Cell Transplantation in Patients with Higher-Risk Myelodysplastic Syndrome.

Azacitidine (AZA) is commonly used in patients with myelodysplastic syndrome (MDS). To determine the role of AZA before allogeneic stem cell transplantation (allo-SCT), we conducted a prospective study of AZA pre-treatment followed by allo-SCT in patients with higher-risk MDS. Twenty-one patients who were scheduled for their third to sixth cycle of AZA pre-treatment followed by allo-SCT were enrolled. AZA pre-treatment was interrupted early in 3 patients (14.3%) because of leukaemic transformation or death. The overall response rate to AZA pre-treatment was 57.1%. There were 2 cases of complete remission, 1 case of partial remission, and 9 cases of haematologic improvement. Fourteen patients (66.7%) received the planned allo-SCT and 5 patients were alive at the last follow-up. Three-year progression-free survival (PFS) and 3-year overall survival (OS) in the 14 patients who received allo-SCT were 30.0% (95% CI 3.3-56.7) and 42.9% (95% CI 17.1-68.7), respectively. PFS and OS were not influenced by response to AZA pre-treatment (p > 0.05). In this study, AZA had a role as a bridge therapy to prevent leukaemic transformation prior to selection of a donor for allo-SCT and showed low toxicity. It may be considered in patients with higher-risk MDS.

Deferasirox improves hematologic and hepatic function with effective reduction of serum ferritin and liver iron concentration in transfusional iron overload patients with myelodysplastic syndrome or aplastic anemia.

BACKGROUND: Transfusional iron overload and its consequences are challenges in chronically transfused patients with myelodysplastic syndromes (MDSs) or aplastic anemia (AA). STUDY DESIGN AND METHODS: This was a prospective, multicenter, open-label study to investigate the efficacy of deferasirox (DFX) by serial measurement of serum ferritin (S-ferritin) level, liver iron concentration (LIC) level using relaxation rates magnetic resonance imaging, and other laboratory variables in patients with MDS or AA. RESULTS: A total of 96 patients showing S-ferritin level of at least 1000 ng/mL received daily DFX for up to 1 year. At the end of the study, S-ferritin level was significantly decreased in MDS (p=0.02366) and AA (p=0.0009). LIC level was also significantly reduced by more than 6.7 mg Fe/g dry weight from baseline. Hemoglobin level and platelet counts were significantly increased from baseline (p=0.002 and p=0.025, respectively) for patients showing significant anemia or thrombocytopenia. Elevated alanine aminotransferase was also significantly decreased from baseline. CONCLUSIONS: This study shows that DFX is effective in reducing S-ferritin and LIC level in transfusional iron overload patients with MDS or AA and is well tolerated. In addition, positive effects in hematologic and hepatic function can be expected with DFX. Iron chelation treatment should be considered in transfused patients with MDS and AA when transfusion-related iron overload is documented.

Investigation on Contact Properties of 2D van der Waals Semimetallic 1T-TiS2/MoS2 Heterojunctions.

Two-dimensional transition metal dichalcogenides (2D TMDCs) are considered promising alternatives to Si as channel materials because of the possibility of retaining their superior electronic transport properties even at atomic body thicknesses. However, the realization of high-performance 2D TMDC field-effect transistors remains a challenge owing to Fermi-level pinning (FLP) caused by gap states and the inherent high Schottky barrier height (SBH) within the metal contact and channel layer. This study demonstrates that high-quality van der Waals (vdW) heterojunction-based contacts can be formed by depositing semimetallic TiS2 onto monolayer (ML) MoS2. After confirming the successful formation of a TiS2/ML MoS2 heterojunction, the contact properties of vdW semimetal TiS2 were thoroughly investigated. With clean interfaces of the TiS2/ML MoS2 heterojunctions, atomic-layer-deposited TiS2 can induce gap-state saturation and suppress FLP. Consequently, compared with conventional evaporated metal electrodes, the TiS2/ML MoS2 heterojunctions exhibit a lower SBH of 8.54 meV and better contact properties. This, in turn, substantially improves the overall performance of the device, including its on-current, subthreshold swing, and threshold voltage. Furthermore, we believe that our proposed strategy for vdW-based contact formation will contribute to the development of 2D materials used in next-generation electronics.

Clinical significance of abnormal serum free light chain ratio: diagnostic confusion or underlying monoclonality?

BACKGROUND: The spectrum of laboratory tests used to detect monoclonal components (M-components) include serum and urine protein electrophoresis (PEP), immunofixation electrophoresis, and immunonephelometric methods such as free light chain assay (sFLC). METHODS: In this study, we retrospectively analyzed 78 patients who were to be tested with FLC without previous evidence of MG in order to investigate the clinical meaning of K/L screening. Abnormal K/L in sFLC was found in 25 samples from 21 patients (21/78, 26.92%). RESULTS: Among them, serum electrophoresis was requested for 16 patients where 5 were diagnosed as either normal or polyclonal gammopathy, 5 as plasma cell myeloma, 5 as monoclonal gammopathy of undetermined significance and I as amyloidosis. In total, 11 patients were revealed to have MG related diseases (11/25, 44.0 %). CONCLUSIONS: The clinical function of sFLC as a MG screening tool turned out to be effective based on the result where 16 out of 21 patients who were subject to further study led to diagnoses of MG related diseases in 11 patients. To provide an accurate evaluation for the performance of sFLC as a screening tool for MG, further studies should include additional confirmation of PEP results for patient groups that showed normal K/L ratios.

Laboratory tools for oligo-secretory myeloma diagnosis: capillary electrophoresis versus free light chain assay.

BACKGROUND: To investigate how capillary electrophoresis (CE) works in oligo-secretory myeloma (OSM), we report a case here of OSM using multiple diagnostic methods including gel electrophoresis (GE), CE, and free light chain assay (sFLC). Also, we provide a brief review of laboratory methods to compare their diagnostic utilities in OSM. METHODS: A 72 year-old Korean male suffering from low back pain during the past 6 months was transferred to the department of neurosurgery in order to evaluate abnormal findings in an imaging study, suggesting plasma cell myeloma (PCM) with multiple bone metastasis. CE showed no suspicious M-component; however, it showed increased Kappa components and skewing Kappa/Lambda ratio (K/L). Bone marrow examination revealed plasma cells observed up to 70%, which were compatible with sFLC results. RESULTS: Based on these results, the diagnosis turned out to be OSM with multiple bone metastases. Thereafter, the patient started the first cycle of chemotherapy accompanied by palliative radiation therapy. CONCLUSIONS: In our case, sFLC showed abnormal Kappa and K/L results from both serum and urine specimen. Therefore, it seems to be more sensitive and appropriate than both GE and CE to diagnose OSM.

Second-line chemotherapy for advanced gastric cancer in Korea.

Stomach cancer is still one of the most prevalent malignancies and is the main cause of cancer deaths worldwide. The outcome for patients with metastasis, as well as for those with tumor recurrence, is dismal, with median survival time not greater than a year. Patients with unresectable locally advanced or metastatic lesions have been treated with systemic chemotherapy, and several randomized studies have demonstrated the benefit of chemotherapy compared with best supportive care. Recently, randomized phase III trials have presented a benefit of second-line chemotherapy compared with supportive care alone. However, it is not known at present which drug is the most effective in this setting. In Korea, the practice of offering second-line treatment to patients with advanced gastric cancer (AGC) is common, and many prospective clinical trials investigating clinical outcomes of second-line chemotherapy have been reported. Therefore, to define the potential role of second-line chemotherapy and to help to select an effective regimen, we review the published Korean prospective data concerning the use of chemotherapy in the second-line setting for the treatment of AGC. No phase III trials but 20 phase II trials were identified. The benefit of second-line chemotherapy in AGC has indirect evidence considering prolongation of progression-free survival (PFS) and improvement of the response rate. Taxanes, irinotecan, and oxaliplatin have been studied much and might be promising drugs considering cross-resistance to a 5-fluorouracil and cisplatin combination (FP). A large, prospective, multicenter, randomized phase III study is warranted to select the most effective second-line chemotherapeutic agents.

Long-term follow-up results of cytarabine-containing chemotherapy for acute promyelocytic leukemia.

BACKGROUND/AIMS: We evaluated the feasibility and long-term efficacy of the combination of cytarabine, idarubicin, and all-trans retinoic acid (ATRA) for treating patients with newly diagnosed acute promyelocytic leukemia (APL). METHODS: We included 87 patients with newly diagnosed acute myeloid leukemia and a t(15;17) or promyelocytic leukemia/retinoic acid receptor alpha (PML-RARα) mutation. Patients received 12 mg/m2/day idarubicin intravenously for 3 days and 100 mg/m2/day cytarabine for 7 days, plus 45 mg/m2/day ATRA. Clinical outcomes included complete remission (CR), relapse-free survival (RFS), overall survival (OS), and the secondary malignancy incidence during a 20-year follow-up. RESULTS: The CR, 10-year RFS, and 10-year OS rates were 89.7%, 94.1%, and 73.8%, respectively, for all patients. The 10-year OS rate was 100% for patients that achieved CR. Subjects were classified according to the white blood cell (WBC) count in peripheral blood at diagnosis (low-risk, WBC < 10,000/mm3; high-risk, WBC ≥ 10,000/mm3). The low-risk group had significantly higher RFS and OS rates than the high-risk group, but the outcomes were not superior to the current standard treatment (arsenic trioxide plus ATRA). Toxicities were similar to those observed with anthracycline plus ATRA, and higher than those observed with arsenic trioxide plus ATRA. The secondary malignancy incidence after APL treatment was 2.7%, among the 75 patients that achieved CR, and 5.0% among the 40 patients that survived more than 5 years after the APL diagnosis. CONCLUSION: Adding cytarabine to anthracycline plus ATRA was not inferior to anthracycline plus ATRA alone, but it was not comparable to arsenic trioxide plus ATRA. The probability of secondary malignancy was low.

Signal transducer and activator of transcription 3 pathway mediates genipin-induced apoptosis in U266 multiple myeloma cells.

It has drawn a lot of attention to target signal transducer and activator of transcription 3 (STAT3) as a potential strategy for cancer therapeutics. Using several myelogenous cell lines, the effect of genipin (an active compound of Gardenia fruit) on the STAT3 pathway and apoptosis was investigated. Genipin suppressed the constitutive STAT3 activation in U266 and U937 cells and stimulated Src homology 2 domain-containing phosphatase 1 (SHP-1), which dephosphorylates and inactivates STAT3. Specifically, genipin blocked STAT3 activation via repressing the activation of c-Src, but not Janus kinase 1 (JAK1). Genipin also downregulated the expression of STAT3 target genes including Bcl-2, Bcl-x(L) , Survivin, Cyclin D1, and VEGF. Conversely, protein tyrosine phosphatase inhibitor pervanadate blocked genipin induced STAT3 inactivation. Using DNA fragmentation or TUNEL assays, we demonstrated the apoptotic effect of genipin on U266, MM.1S, and U937 cells. Furthermore, genipin effectively potentiated the cytotoxic effect of chemotherapeutic agents, such as bortezomib, thalidomide, and paclitaxel in U266 cells. Our data suggest that through regulation of Src and SHP-1, genipin antagonizes STAT3 for the induction of apoptosis in myeloma cells.

Hydrogen Barriers Based on Chemical Trapping Using Chemically Modulated Al2O3 Grown by Atomic Layer Deposition for InGaZnO Thin-Film Transistors.

In this study, the excellent hydrogen barrier properties of the atomic-layer-deposition-grown Al2O3 (ALD Al2O3) are first reported for improving the stability of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs). Chemical species in Al2O3 were artificially modulated during the ALD process using different oxidants, such as H2O and O3 (H2O-Al2O3 and O3-Al2O3, respectively). When hydrogen was incorporated into the H2O-Al2O3-passivated TFT, a large negative shift in Vth (ca. -12 V) was observed. In contrast, when hydrogen was incorporated into the O3-Al2O3-passivated TFT, there was a negligible shift in Vth (ca. -0.66 V), which indicates that the O3-Al2O3 has a remarkable hydrogen barrier property. We presented a mechanism for trapping hydrogen in a O3-Al2O3 via various chemical and electrical analyses and revealed that hydrogen molecules were trapped by C-O bonds in the O3-Al2O3, preventing the inflow of hydrogen to the a-IGZO. Additionally, to minimize the deterioration of the pristine device that occurs after a barrier deposition, a bi-layered hydrogen barrier by stacking H2O- and O3-Al2O3 is adopted. Such a barrier can provide ultrastable performance without degradation. Therefore, we envisioned that the excellent hydrogen barrier suggested in this paper can provide the possibility of improving the stability of devices in various fields by effectively blocking hydrogen inflows.

Low incidence of clinically apparent thromboembolism in Korean patients with multiple myeloma treated with thalidomide.

The frequency of thromboembolic events (TE) in Caucasian patients with multiple myeloma (MM) receiving thalidomide as the initial treatment has been reported to be 10~58% without prophylactic anticoagulation. Korean MM patients treated with thalidomide were studied to determine the frequency of TE and associated risk factors. A retrospective medical record review of the Korean MM registry from 25 centers in Korea between 2003 and 2007 was performed. We assessed the incidence of arterial and venous TE and the associated clinical parameters. Three hundred and sixty MM patients (median age 61 years, range 32-88 years) received thalidomide treatment. Fourteen patients (3.9%) developed TE: 12 had venous and two had arterial locations. The sites for the venous TE included lungs (seven), lower extremities (four), upper extremities (one), and neck (one). Arterial TE developed in cerebral and peripheral arteries each. No single clinical parameter such as prerequisite for the metabolic syndrome, disease status, and treatment regimen were predictive for the development of TE. The frequency of TE in patients who received thalidomide as initial therapy (7/155) was not different from those who received thalidomide for progressive or relapsed disease (7/205, p = 0.592). The frequency of TE during thalidomide treatment in Korean patients with MM was low. No significant clinical factor was found to be a risk factor. The subgroup requiring thromboprophylaxis among the Korean patients with MM, receiving thalidomide, needs to be clarified.

Re-analysis of the outcomes of post-remission therapy for acute myeloid leukemia with core binding factor according to years of patient enrollment.

OBJECTIVE: The purpose of this study was to re-evaluate post-remission therapy outcomes after first remission according to years of patient enrollment in patients with core binding factor acute myeloid leukaemia. METHODS: We conducted a retrospective study on 138 patients aged less than 60 years diagnosed with core binding factor acute myeloid leukaemia between 1994 and 2006, comparing allogeneic stem cell transplantation and high-dose cytarabine chemotherapy as post-remission treatment options after the first remission. RESULTS: The 5-year probabilities of disease-free survival and overall survival were not different between allogeneic stem cell transplantation and high-dose cytarabine groups. However, 3-year probabilities of disease-free survival (86.7% vs. 67.0%) and overall survival (90.0% vs. 67.3%) showed a trend towards improvement in the allogeneic stem cell transplantation group compared with the high-dose cytarabine group in cohort after 2003 (2003-2006), whereas outcomes were not different in cohort before 2003 (1994-2002). Especially, 3-year probabilities of disease-free survival (95.2% vs. 59.3%, P = 0.008) and overall survival (95.2% vs. 59.6%, P = 0.032) of allogeneic stem cell transplantation group were significantly better than high-dose cytarabine group in cohort after 2003 of acute myeloid leukaemia patients with t(8;21). The relative risk of overall survival with allogeneic stem cell transplantation, compared with high-dose cytarabine chemotherapy, was significantly improved in the cohort after 2003 (0.33; 95% CI, 0.07-1.48) when compared with that before 2003 (1.92; 95% CI, 0.77-4.82). In multivariate analysis in cohort after 2003, allogeneic stem cell transplantation as post-remission therapy was associated with better disease-free survival. CONCLUSIONS: Allogeneic stem cell transplantation is currently the more effective post-remission therapy than it was prior to 2003 for core binding factor acute myeloid leukaemia achieving first remission. On the contrary to previous findings, allogeneic stem cell transplantation provides significantly improved outcomes than high-dose cytarabine chemotherapy in acute myeloid leukaemia with t(8;21).

Korean patients with superwarfarin intoxication and their outcome.

This observational study aimed at evaluating recent superwarfarin intoxication of Korean patients. Ten patients were diagnosed as or highly suspicious for superwarfarin intoxication. Case report forms described by attending hematologists of the patients were collected and analyzed. Bleeding symptoms were varied among the patients. Patients uniformly showed prolonged prothrombin time (PT) and activated thromboplastin time (aPTT) with decreased activity of vitamin K dependent coagulation factors. Positive serum brodifacoum test results in 4 of 5 requested patients contributed to confirmatory diagnosis. Psychiatric interview revealed an attempted ingestion in one patient. High dose vitamin K1 therapy promptly corrected prolonged PT and aPTT, but hasty discontinuation caused repeated bleeding diathesis in 6 patients. Route of intoxication was unknown or not definite among 8 of 10 patients. Three patients had a possibility of environmental exposure considering their occupations: there might be intoxication by transdermal absorption or inhalation. Therefore, high dose and prolonged use of vitamin K1 therapy is necessary for effective detoxification. Further detailed investigation on environmental exposure and efforts to improve availability of the blood level test in clinic are requested.

Korean guidelines for the prevention of venous thromboembolism.

This guideline focuses on the primary prevention of venous thromboembolism (VTE) in Korea. The guidelines should be individualized and aim at patients scheduled for major surgery, as well as patients with a history of trauma, high-risk pregnancy, cancer, or other severe medical illnesses. Currently, no nation-wide data on the incidence of VTE exist, and randomized controlled trials aiming at the prevention of VTE in Korea have yielded few results. Therefore, these guidelines were based on the second edition of the Japanese Guidelines for the Prevention of VTE and the eighth edition of the American College of Chest Physicians (ACCP) Evidenced-Based Clinical Practice Guidelines. These guidelines establish low-, moderate-, and high-risk groups, and recommend appropriate thromboprophylaxis for each group.

Vascular events in Korean patients with myeloproliferative neoplasms and their relationship to JAK2 mutation.

Evaluation of the Janus kinase 2 (JAK2) V617F mutation has been widely used for the diagnosis of myeloproliferative neoplasms (MPN). However, its prognostic relevance to clinical outcome is not completely understood. We investigated the association of JAK2 V617F with vascular events in Korean patients with myeloproliferative neoplasms (MPN). We studied 283 patients from 15 centers, who were diagnosed with MPN. The JAK2 V617F status was evaluated by allele-specific polymerase chain reaction (PCR) and sequencing. The patients' diagnoses were essential thrombocythemia (ET n = 146), polycythemia vera (PV n = 120), primary myelofibrosis (n = 12), and unclassifiable MPN (MPNu n = 5). JAK2 V617F was detected in 89 (61%) patients with ET, 103 (86%) with PV, four (33%) with myelofibrosis, and four (80%) with MPNu. A higher number of leukocytes, haemoglobin levels and BM cellularity as well as an older age, lower platelet counts, and diagnosis of PV were significantly correlated with JAK2 V617F. Eighty-three and 43 episodes of thrombosis and bleeding occurred in 100 patients each before and after the diagnosis. Vascular events more frequently occurred in 37% of patients with JAK2 V617F than in 29% of those without the mutation (p = 0.045). Among 175 patients whose samples were available for sequencing, 28 patients with homozygous JAK2 V617F had vascular events more frequently (57%) than those who were heterozygotes (39%) or had the wild type (27%) (p = 0.03). The multivariate analysis showed that a JAK2 homozygous mutation, hypercholesterolemia and older age were independent risk factors for a vascular event. The results of this study showed that Korean patients with MPN had a similar JAK2 mutation rate and frequency of vascular events when compared to Western patients. The presence of V617F was significantly related to vascular events. Therefore, initial evaluation for the JAK2 mutation and careful monitoring for vascular events should be performed in MPN patients.