Nucleolar URB1 ensures 3' ETS rRNA removal to prevent exosome surveillance.

The nucleolus is the most prominent membraneless condensate in the nucleus. It comprises hundreds of proteins with distinct roles in the rapid transcription of ribosomal RNA (rRNA) and efficient processing within units comprising a fibrillar centre and a dense fibrillar component and ribosome assembly in a granular component1. The precise localization of most nucleolar proteins and whether their specific localization contributes to the radial flux of pre-rRNA processing have remained unknown owing to insufficient resolution in imaging studies2-5. Therefore, how these nucleolar proteins are functionally coordinated with stepwise pre-rRNA processing requires further investigation. Here we screened 200 candidate nucleolar proteins using high-resolution live-cell microscopy and identified 12 proteins that are enriched towards the periphery of the dense fibrillar component (PDFC). Among these proteins, unhealthy ribosome biogenesis 1 (URB1) is a static, nucleolar protein that ensures 3' end pre-rRNA anchoring and folding for U8 small nucleolar RNA recognition and the subsequent removal of the 3' external transcribed spacer (ETS) at the dense fibrillar component-PDFC boundary. URB1 depletion leads to a disrupted PDFC, uncontrolled pre-rRNA movement, altered pre-rRNA conformation and retention of the 3' ETS. These aberrant 3' ETS-attached pre-rRNA intermediates activate exosome-dependent nucleolar surveillance, resulting in decreased 28S rRNA production, head malformations in zebrafish and delayed embryonic development in mice. This study provides insight into functional sub-nucleolar organization and identifies a physiologically essential step in rRNA maturation that requires the static protein URB1 in the phase-separated nucleolus.

Phillygenin Alleviates Arthritis through the Inhibition of the NLRP3 Inflammasome and Ferroptosis by AMPK.

We investigated the potential arthritis-inducing effects of Phillygenin and its underlying mechanisms. RAW264.7 cells were stimulated with lipopolysaccharide to induce inflammation. Phillygenin was found to reduce arthritis score, histopathological changes, paw edema, spleen index, and ALP levels in a dose-dependent manner in a model of arthritis. Additionally, Phillygenin was able to decrease levels of inflammation markers in serum samples of mice with arthritis and also inhibited inflammation markers in the cell supernatant of an in vitro model of arthritis. Phillygenin increased cell viability and JC-1 disaggregation, enhanced calcien-AM/CoCl2, reduced LDH activity levels and IL-1a levels, and inhibited Calcein/PI levels and iron concentration in an in vitro model. Phillygenin was also found to reduce ROS-induced oxidative stress and Ferroptosis, and suppress the NLRP3 inflammasome in both in vivo and in vitro models through AMPK. In the in vivo model, Phillygenin was observed to interact with AMPK protein. These findings suggest that Phillygenin may be a potential therapeutic target for preventing arthritis by inhibiting NLRP3 inflammasome and Ferroptosis through AMPK. This indicates that Phillygenin could have disease-modifying effects on arthritis.

Epigenetic inactivation of the 5-methylcytosine RNA methyltransferase NSUN7 is associated with clinical outcome and therapeutic vulnerability in liver cancer.

BACKGROUND: RNA modifications are important regulators of transcript activity and an increasingly emerging body of data suggests that the epitranscriptome and its associated enzymes are altered in human tumors. METHODS: Combining data mining and conventional experimental procedures, NSUN7 methylation and expression status was assessed in liver cancer cell lines and primary tumors. Loss-of-function and transfection-mediated recovery experiments coupled with RNA bisulfite sequencing and proteomics determined the activity of NSUN7 in downstream targets and drug sensitivity. RESULTS: In this study, the initial screening for genetic and epigenetic defects of 5-methylcytosine RNA methyltransferases in transformed cell lines, identified that the NOL1/NOP2/Sun domain family member 7 (NSUN7) undergoes promoter CpG island hypermethylation-associated with transcriptional silencing in a cancer-specific manner. NSUN7 epigenetic inactivation was common in liver malignant cells and we coupled bisulfite conversion of cellular RNA with next-generation sequencing (bsRNA-seq) to find the RNA targets of this poorly characterized putative RNA methyltransferase. Using knock-out and restoration-of-function models, we observed that the mRNA of the coiled-coil domain containing 9B (CCDC9B) gene required NSUN7-mediated methylation for transcript stability. Most importantly, proteomic analyses determined that CCDC9B loss impaired protein levels of its partner, the MYC-regulator Influenza Virus NS1A Binding Protein (IVNS1ABP), creating sensitivity to bromodomain inhibitors in liver cancer cells exhibiting NSUN7 epigenetic silencing. The DNA methylation-associated loss of NSUN7 was also observed in primary liver tumors where it was associated with poor overall survival. Interestingly, NSUN7 unmethylated status was enriched in the immune active subclass of liver tumors. CONCLUSION: The 5-methylcytosine RNA methyltransferase NSUN7 undergoes epigenetic inactivation in liver cancer that prevents correct mRNA methylation. Furthermore, NSUN7 DNA methylation-associated silencing is associated with clinical outcome and distinct therapeutic vulnerability.

ASXL1 mutations accelerate bone marrow fibrosis via EGR1-TNFA axis-mediated neoplastic fibrocyte generation in myeloproliferative neoplasms.

Apart from the central role of the activated JAK/STAT signaling pathway, ASXL1 mutations are the most recurrent additional mutations in myeloproliferative neoplasms and occur much more commonly in myelofibrosis than in essential thrombocythemia and polycythemia vera. However, the mechanism of the association with ASXL1 mutations and bone marrow fibrosis remains unknown. Here, integrating our own data from patients with myeloproliferative neoplasms and a hematopoietic-specific Asxl1 deletion/Jak2V617F mouse model, we show that ASXL1 mutations are associated with advanced myeloproliferative neoplasm phenotypes and onset of myelofibrosis. ASXL1 mutations induce skewed monocyte/macrophage and neoplastic monocyte-derived fibrocyte differentiation, consequently they enhance inflammation and bone marrow fibrosis. Consistently, the loss of ASXL1 and JAK2V617F mutations in hematopoietic stem and progenitor cells leads to enhanced activation of polycomb group target genes, such as EGR1. The upregulation of EGR1, in turn, accounts for increased hematopoietic stem and progenitor cell commitment to the monocyte/macrophage lineage. Moreover, EGR1 induces the activation of TNFA and thereby further drives the differentiation of monocytes to fibrocytes. Accordingly, combined treatment with a TNFR antagonist and ruxolitinib significantly reduces fibrocyte production in vitro. Altogether, these findings demonstrate that ASXL1 mutations accelerate fibrocyte production and inflammation in myeloproliferative neoplasms via the EGR1-TNFA axis, explaining the cellular and molecular basis for bone marrow fibrosis and the proof-ofconcept for anti-fibrosis treatment.

Ruxolitinib combined with prednisone, thalidomide and danazol in patients with myelofibrosis: Results of a pilot study.

Ruxolitinib is a safe and effective therapy of myeloproliferative neoplasm-associated (MPN) myelofibrosis. However, often there are dose reductions and/or therapy interruptions because of therapy-related adverse events (AEs), especially anemia and thrombocytopenia. We previously reported combined therapy with prednisone, thalidomide and danazol (PTD) reversed anemia and thrombocytopenia in people with MPN-associated myelofibrosis. We wondered whether adding PTD to ruxolitinib might mitigate the hematologic AEs and thereby avoid the dose reduction of ruxolitinib and improve the efficacy. To test this hypothesis, we conducted a baseline hemoglobin and platelet concentration assignment prospective observational study in 72 patients comparing 3-month dose adjustment and efficacy of ruxolitinib with (N = 53, the study group) or without (N = 19, the control group) PTD. According to the platelet counts, the median daily ruxolitinib doses in the study group increased from 30 to 40 mg by week 12, whereas in the control group it remained at 30 mg (p = 0.019). In the study group 35 patients had a hemoglobin increase ≥10 g/L compared with no patient receiving ruxolitinib only (p < 0.001). Platelet increases >100 × 10E+9/L were seen in 56.6% and 5.3% of patients in the two groups, respectively (p < 0.001). In patients with anemia and thrombocytopenia, 18 patients in the study group had an anemia response at week 12 and 12 had a platelet increase of ≥50 × 10E+9/L. No patient in the control group achieved either response (p < 0.001 and p = 0.078). The study group had a more spleen response than the control group (p = 0.046). Peripheral edema and transaminase elevation were the main nonhematologic AEs of PTD. These AEs can be alleviated by adjusting the danazol dose. In conclusion, adding PTD to ruxolitinib improved ruxolitinib-associated anemia and thrombocytopenia, and resulted in a higher ruxolitinib dose.

Electric Polarization Switching on an Atomically Thin Metallic Oxide.

Materials with reduced dimensions have been shown to host a wide variety of exotic properties and novel quantum states that often defy textbook wisdom. Polarization switching and metallic screening are well-known examples of mutually exclusive properties that cannot coexist in bulk solids. Here we report the fabrication of (SrRuO3)1/(BaTiO3)10 superlattices that exhibits reversible polarization switching in an atomically thin metallic layer. A multipronged investigation combining structural analyses, electrical measurements, and first-principles electronic structure calculations unravels the coexistence of two-dimensional (2D) metallicity in the SrRuO3 layer accompanied by the breaking of inversion symmetry, supporting electric polarization along the out-of-plane direction. Such a 2D ferroelectric-like metal paves a novel way to engineer a quantum multistate with unusual coexisting properties, such as ferroelectrics and metals, manipulated by external fields.

Effect of Endoscopic Appendix Intubation and Irrigation on Acute Uncomplicated Appendicitis.

OBJECTIVE: To investigate the efficacy and safety of endoscopic appendix intubation and irrigation (EAI) on acute uncomplicated appendicitis. METHODS: This prospective non-randomized study examined 169 patients with suspected acute uncomplicated appendicitis at The First Affiliated Hospital of Fujian Medical University from October 2015 to 2017. Patients were divided into three groups: endoscopic appendix intubation and irrigation (EAI, n = 18), laparoscopic appendectomy (LA, n = 87), and antibiotic alone (A, n = 64). The treatment success rate, duration of hospitalization, medical costs, operation time, duration of abdominal pain, fasting time, complications, and recurrence were analyzed. RESULTS: The three groups had no significant differences in baseline characteristics (age, gender, Alvarado score, white blood cell count, and neutrophil count; all P > 0.05). Compared to the LA group, the EAI group had shorter durations of the operation, fasting, and abdominal pain; less use of oral and intravenous antibiotics; and lower medical costs (all P < 0.05). Compared to the A group, the EAI group had shorter durations of abdominal pain and hospitalization, and less use of intravenous antibiotics (all P < 0.05). The EAI group had no complications, but 3 patients (3.4%) in the LA group had surgery-related complications. CONCLUSION: EAI is a safe and effective treatment for acute uncomplicated appendicitis. Patients who received EAI had shorter durations of abdominal pain and hospitalization than those who received LA or conservative antibiotic treatment. TRIAL REGISTRATION NUMBER AND AGENCY: ChiCTR-IPN-15006565, Chinese Clinical Trial Registry.

The Middle Road Less Taken: Electronic-Structure-Inspired Design of Hybrid Photocatalytic Platforms for Solar Fuel Generation.

The development of efficient solar energy conversion to augment other renewable energy approaches is one of the grand challenges of our time. Water splitting, or the disproportionation of H2O into energy-dense fuels, H2 and O2, is undoubtedly a promising strategy. Solar water splitting involves the concerted transfer of four electrons and four protons, which requires the synergistic operation of solar light harvesting, charge separation, mass and charge transport, and redox catalysis processes. It is unlikely that individual materials can mediate the entire sequence of charge and mass transport as well as energy conversion processes necessary for photocatalytic water splitting. An alternative approach, emulating the functioning of photosynthetic systems, involves the utilization of hybrid systems wherein different components perform the various functions required for solar water splitting. The design of such hybrid systems requires the multiple components to operate in lockstep with optimal thermodynamic driving forces and interfacial charge transfer kinetics. This Account describes a new class of nanoscale heterostructures comprising M xV2O5 nanowires, where M is a p-block cation with a ( n - 1) d10 ns2 np0 electronic configuration characterized by a stereoactive lone pair of electrons and x is its stoichiometry, interfaced with II-VI semiconductor quantum dots (QDs). Photocatalytic water splitting involves the transfer of excited-state holes from QDs to mid-gap states (derived from the stereoactive lone pairs of p-block cations) of nanowires, hole transport through nanowires, the reduction of protons at a QD-immobilized catalyst, and water oxidation at an anode. The M xV2O5/QD architectures provide a vast design space for evolutionary optimization of function with considerable tunability of composition and structure of the individual components as well as of the interfacial structure, thereby facilitating programmability of absorption spectra, energetic offsets, and charge-transfer reactivity. The available design space spans choice of the p-block cation M, its stoichiometry x, the composition and size of various QDs, and the nature of the nanowire/QD interface. This multivariate parameter space has been navigated by integrating first-principles modeling, diversified synthesis, spectroscopic measurements, and catalytic evaluation to facilitate the rational design of several generations of heterostructures and the systematic improvement of their photocatalytic performance. The electronic structures of the target heterostructures are predicted by DFT calculations in light of the revised lone pair model of stereoactive structural distortions and evaluated by hard X-ray photoelectron spectroscopy such as to systematically tune the interfacial band offsets. Central to this approach is the development of a topochemical "etch-a-sketch" intercalation approach that allows for facile installation of p-block cations in metastable polymorphs of V2O5. The interfacial charge transfer kinetics of M xV2O5/QD heterostructures is further evaluated by transient absorption spectroscopy to measure excited-state charge-transfer dynamics and is found to depend sensitively on interfacial structure and the thermodynamic driving forces in accordance with Marcus theory. The integration of theory and experiment has allowed for the design of viable photocatalytic architectures exemplified by the exceptional catalytic performance of ß-Pb xV2O5/CdX (X= S, Se) architectures, which has subsequently been elaborated to other lone-pair M xV2O5 compounds, demonstrating the effective exploitation of the opportunities for programmability available in the design space.

Hole Extraction by Design in Photocatalytic Architectures Interfacing CdSe Quantum Dots with Topochemically Stabilized Tin Vanadium Oxide.

Tackling the complex challenge of harvesting solar energy to generate energy-dense fuels such as hydrogen requires the design of photocatalytic nanoarchitectures interfacing components that synergistically mediate a closely interlinked sequence of light-harvesting, charge separation, charge/mass transport, and catalytic processes. The design of such architectures requires careful consideration of both thermodynamic offsets and interfacial charge-transfer kinetics to ensure long-lived charge carriers that can be delivered at low overpotentials to the appropriate catalytic sites while mitigating parasitic reactions such as photocorrosion. Here we detail the theory-guided design and synthesis of nanowire/quantum dot heterostructures with interfacial electronic structure specifically tailored to promote light-induced charge separation and photocatalytic proton reduction. Topochemical synthesis yields a metastable ß-Sn0.23V2O5 compound exhibiting Sn 5s-derived midgap states ideally positioned to extract photogenerated holes from interfaced CdSe quantum dots. The existence of these midgap states near the upper edge of the valence band (VB) has been confirmed, and ß-Sn0.23V2O5/CdSe heterostructures have been shown to exhibit a 0 eV midgap state-VB offset, which underpins ultrafast subpicosecond hole transfer. The ß-Sn0.23V2O5/CdSe heterostructures are further shown to be viable photocatalytic architectures capable of efficacious hydrogen evolution. The results of this study underscore the criticality of precisely tailoring the electronic structure of semiconductor components to effect rapid charge separation necessary for photocatalysis.

Associations between gender, disease features and symptom burden in patients with myeloproliferative neoplasms: an analysis by the MPN QOL International Working Group.

The myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and myelofibrosis, are distinguished by their debilitating symptom profiles, life-threatening complications and profound impact on quality of life. The role gender plays in the symptomatology of myeloproliferative neoplasms remains under-investigated. In this study we evaluated how gender relates to patients' characteristics, disease complications and overall symptom expression. A total of 2,006 patients (polycythemia vera=711, essential thrombocythemia=830, myelofibrosis=460, unknown=5) were prospectively evaluated, with patients completing the Myeloproliferative Neoplasm-Symptom Assessment Form and Brief Fatigue Inventory Patient Reported Outcome tools. Information on the individual patients' characteristics, disease complications and laboratory data was collected. Consistent with known literature, most female patients were more likely to have essential thrombocythemia (48.6% versus 33.0%; P<0.001) and most male patients were more likely to have polycythemia vera (41.8% versus 30.3%; P<0.001). The rate of thrombocytopenia was higher among males than females (13.9% versus 8.2%; P<0.001) and males also had greater red-blood cell transfusion requirements (7.3% versus 4.9%; P=0.02) with shorter mean disease duration (6.4 versus 7.2 years, P=0.03). Despite there being no statistical differences in risk scores, receipt of most therapies or prior complications (hemorrhage, thrombosis), females had more severe and more frequent symptoms for most individual symptoms, along with overall total symptom score (22.8 versus 20.3; P<0.001). Females had particularly high scores for abdominal-related symptoms (abdominal pain/discomfort) and microvascular symptoms (headache, fatigue, insomnia, concentration difficulties, dizziness; all P<0.01). Despite complaining of more severe symptom burden, females had similar quality of life scores to those of males. The results of this study suggest that gender contributes to the heterogeneity of myeloproliferative neoplasms by influencing phenotypic profiles and symptom expression.

Pinning down high-performance Cu-chalcogenides as thin-film solar cell absorbers: A successive screening approach.

Photovoltaic performances of Cu-chalcogenides solar cells are strongly correlated with the absorber fundamental properties such as optimal bandgap, desired band alignment with window material, and high photon absorption ability. According to these criteria, we carry out a successive screening for 90 Cu-chalcogenides using efficient theoretical approaches. Besides the well-recognized CuInSe2 and Cu2ZnSnSe4 materials, several novel candidates are identified to have optimal bandgaps of around 1.0-1.5 eV, spike-like band alignments with CdS window layer, sharp photon absorption edges, and high absorption coefficients. These new systems have great potential to be superior absorbers for photovolatic applications if their carrrier transport and defect properties are properly optimized.

Sevoflurane induces cognitive impairments via the MiR-27b/LIMK1-signaling pathway in developing rats.

Exposure to sevoflurane in neonatal rats could induce learning deficits and abnormal social behaviors, but the specific molecular mechanism is unknown. Postnatal day-7 SD rats were treated with 3% sevoflurane plus 30% oxygen/air or 30% oxygen/air. As the rats grew, the Morris water maze (MWM) and fear conditioning tests were performed to evaluate cognitive function, while the expression of LIMK1 was analyzed by western blot. Luciferase reporter assay was performed to investigate the interaction between LIMK1 and miR-27b. The expression of miR-27b was measured by real-time polymerase chain reaction (PCR) after exposure to sevoflurane. Once the miR-27b inhibitor was transfected into the neurons, the expression of LIMK1 was analyzed by real-time PCR and western blot. Exposure to sevoflurane in neonatal rats induced memory and learning impairments according to the MWM and fear conditioning tests. Sevoflurane increased the expression of miR-27b and reduced the expression of LIMK1 in the brain tissues of rats compared to the control group. The results of the luciferase reporter assay showed that LIMK1 was a direct target of miR-27b. In the primary neurons, the inhibition of miR-27b could reverse the down-regulating effects of sevoflurane on LIMK1 expression. We suggest that sevoflurane-induced learning and memory impairments in rats might be mediated via the miR-27b-LIMK1-signaling pathway.

Chalcogenide perovskites for photovoltaics.

Chalcogenide perovskites are proposed for photovoltaic applications. The predicted band gaps of CaTiS3, BaZrS3, CaZrSe3, and CaHfSe3 with the distorted perovskite structure are within the optimal range for making single-junction solar cells. The predicted optical absorption properties of these materials are superior compared with other high-efficiency solar-cell materials. Possible replacement of the alkaline-earth cations by molecular cations, e.g., (NH3NH3)(2+), as in the organic-inorganic halide perovskites (e.g., CH3NH3PbI3), are also proposed and found to be stable. The chalcogenide perovskites provide promising candidates for addressing the challenging issues regarding halide perovskites such as instability in the presence of moisture and containing the toxic element Pb.

High intrinsic carrier mobility and photon absorption in the perovskite CH3NH3PbI3.

The carrier transport and optical properties of the hybrid organic-inorganic perovskite CH3NH3PbI3 are investigated using first-principles approaches. We found that the electron and hole mobilities could reach surprisingly high values of 7-30 × 10(3) and 1.5-5.5 × 10(3) cm(2) V(-1) s(-1), respectively, and both are estimated to be much higher than the current experimental measurements. The high carrier mobility is ascribed to the intrinsically small effective masses of anti-bonding band-edge states. The above results imply that there is still space to improve the performance of related solar cells. This material also has a sharp photon absorption edge and an absorption coefficient as high as 10(5) cm(-1), both of which contribute to effective utilization of solar radiation. Although band-edge states are mainly derived from the inorganic ions of Pb and I, thermal movement of the organic base has indirect influences on the bandgap and carrier effective masses, resulting in the temperature-dependent solar cell efficiencies.

[Pathological diagnosis of pediatric Burkitt lymphoma involving bone marrow].

OBJECTIVE: To investigate pathologic and differential diagnostic features of pediatric Burkitt lymphoma (BL). METHODS: A total of 20 cases of pediatric BL were retrospectively reviewed for their clinical and pathologic profiles. Bone marrow aspiration specimens were available in all cases and bone marrow biopsies were available for immunohistochemical study in 18 cases. Flow cytometry study was available in 16 cases. MYC translocation by FISH method was performed in 11 cases. RESULTS: Atypical lymphocytes with cytoplasmic vacuoles were found in bone marrow smears in all 20 cases and peripheral blood films in all 19 available cases. The bone marrow biopsies showed infiltration by uniform medium-sized atypical lymphocytes with multiple small nucleoli but without the starry-sky pattern in all 18 cases. Immunohistochemistry showed the following results in all 18 cases: positive for CD20, PAX-5, CD10, CD34 and TdT, but negative for bcl-2 and CD3 with Ki-67 > 95%.Flow cytometry showed CD19+CD20+CD10+FMC7+CD22+TdT-CD3- in 16 cases, including κ+ in 8 cases, λ+ in 7 cases, and κ-λ- in 1 case. MYC gene rearrangement by FISH was observed in 10 of the 11 cases. CONCLUSIONS: The histopathology of BL is distinct, including atypical lymphocytes with cytoplasmic vacuoles in bone marrow aspirate, lack of starry-sky patternin bone marrow biopsy. Generally, the diagnosis should be made with a combined immunophenotype and FISH approach. Pediatric BL must be distinguished from DLBCL and B-cell lymphoma, unclassifiable, which has intermediate features between DLBCL and Burkitt lymphoma.

[Clinical features of childhood refractory cytopenia].

OBJECTIVE: To study the clinical features of patients with refractory cytopenia of childhood (RCC). METHODS: The clinical data of 1 420 children (0-14 years old) with an initial diagnosis of non-severe aplastic anemia between January 1990 and June 2013 were retrospectively analyzed. Bone marrow cell morphology and histopathology were re-evaluated, and the patients were re-classified using the criteria proposed in the 2008 edition of the World Health Organization classification of RCC in hematopoietic and lymphoid tumor tissues. The clinical outcomes were followed up every 3-6 months. RESULTS: Among all the 1 420 cases, 152 (10.7%) were reassessed as RCC. Patients with RCC had a lower level of hemoglobin and a higher percentage of fetal hemoglobin than those with non-severe aplastic anemia. Of the patients with RCC, 21.5% showed abnormal karyotypes at diagnosis. The median follow-up period for all patients was 36 months (ranging from 1 to 283 months). The rates of complete response, partial response, and no response to cyclosporine and androgen treatment in RCC patients were 19.0%, 26.7%, and 54.3%, respectively. The 5- and 10-year prospective overall survival rates of RCC patients were 87.9% and 72.4%, respectively. The 5- and 10-year prospective clonal evolution rates were 15.3% and 20.0%, respectively. The 2-year prospective incidence of newly diagnosed karyotype abnormality after the initial diagnosis was 3.6%. The 5- and 10-year prospective leukemia transformation rates were 10.0% and 20.0%, respectively. CONCLUSIONS: RCC shows clinical features similar to adult myelodysplastic syndrome. Children with RCC have a poor prognosis, an increased risk of transformation to leukemia, and a low response rate to cyclosporine treatment.

Unique features of primary myelofibrosis in Chinese.

Clinical and laboratory features of 642 consecutive Chinese subjects with primary myelofibrosis (PMF) were analyzed and compared with those of 1054 predominately white subjects with PMF. Chinese subjects were significantly younger, fewer had constitutional symptoms, and fewer had a palpable spleen or liver. Anemia, in contrast, was significantly more common in Chinese as was an increased white blood cell count and low platelet count. The reason for these differences is unclear, but it does not seem to be correlated with delayed diagnosis. A small but significantly increased proportion of Chinese had the JAK2(V617F) mutation but no difference in the frequency of haplotypes associated with PMF in whites. Survival of Chinese with PMF was also significantly longer than that of whites with PMF. We found commonly used staging systems for PMF such as the International Prognostic Scoring System and the Dynamic International Prognostic Scoring System were suboptimal predictors of survival in Chinese with PMF, and we developed a revised prognostic score that should help in comparison of data between studies of PMF in different populations and planning of clinical trials.

Calreticulin mutations in Chinese with primary myelofibrosis.

We tested 357 Chinese with primary myelofibrosis for mutations in CALR, JAK2 and MPL. CALR mutations were detected in 76 subjects (21%). There were 24 (32%) type-1 (L367fs*46) and 49 (64%) type-2 (K385fs*47) mutations. Seventy-two of 168 subjects (43%) without a JAK2 or MPL mutation had a CALR mutation. Subjects with a type-2 CALR mutation had lower hemoglobin concentrations (P=0.001), lower WBC counts (P<0.001), a higher percentage of blood blasts (P=0.009), and higher conventional (P<0.001) and Chinese-adjusted Dynamic International Prognostic Scoring System (P<0.001) scores compared with subjects with JAK2 mutations. Subjects with a type-2 CALR mutation were also likely to have abnormal platelet levels (<100 × 10(9)/L, P=0.01 or >450 × 10(9)/L, P=0.042) and no splenomegaly (P=0.004). Type-2 CALR mutation or no detectable mutation was an independent high-risk factor for survival in multivariate analyses. These data suggest the ratio between type-1 and type-2 mutations is reversed in Chinese with primary myelofibrosis compared with populations of subjects with primary myelofibrosis of predominately European descent. The unfavorable prognostic impact of CALR mutations in Chinese with primary myelofibrosis is only seen in those with type-2 mutations. These data underscore the need to evaluate the prognostic impact of genetic mutations in different populations.