Estudio de mutaciones en neoplasias mieloproliferativas Philadelphia negativas en un hospital público chileno / Search for mutations in patients with Philadelphia negative myeloproliferative neoplasms in a public hospital in Chile

BACKGROUND: Philadelphia negative myeloproliferative neoplasms (Ph-MPN) are clonal disorders whose pathogenesis has been elucidated in recent years, creating diagnostic and prognostic algorithms. AIM: To study JAK2, CALR y MPL gene mutations in patients with Ph-MPN. MATERIALS AND METHODS: Descriptive cross-sectional observational study of patients with MPN (2015-2019), reviewing clinical, demographic and laboratory data. JAK2, CALR and MPL gene mutations were analyzed by RT-PCR. Results: We studied 72 patients. Fifty percent had essential thrombocythemia (ET), 26.4% had polycythemia vera (PV) and 23.6% had primary myelofibrosis (PM). Bone marrow biopsy was available in 76.5%. At diagnosis, the mean age was 65.5 years and 61% were symptomatic. A thrombotic event was the most frequent problem in 20% and 25% had splenomegaly. There were statistically significant differences in hematological parameters between the different MPNs. JAK2 V617F mutation was detected in 61.1%. Only 19 JAK2 V617F negative patients were available for CALR and MPL mutation studies, identifying 10 triple negative cases. Kaplan Meier curves showed a median survival of 88 months, being similar in the three MPNs. Causes of death in 20 patients were thrombotic complications in 30%, disease progression in 25%, infection in 20%, other neoplasms in 15% and other causes in 10%. CONCLUSIONS: The presentation and frequency of JAK2 V617F, CALR and MPL mutations in our cohort was similar to those reported in other studies for ET and PM. JAK2 V617F mutation was lower for PV. No significant differences between the three MPNs were observed for overall survival. We could not assess the prognostic value of the mutations.

IRF4 and IRF8 expression are associated with clinical phenotype and clinico-hematological response to hydroxyurea in essential thrombocythemia / 医学前沿

The morbidity and mortality of myeloproliferative neoplasms (MPNs) are primarily caused by arterial and venous complications, progression to myelofibrosis, and transformation to acute leukemia. However, identifying molecular-based biomarkers for risk stratification of patients with MPNs remains a challenge. We have previously shown that interferon regulatory factor-8 (IRF8) and IRF4 serve as tumor suppressors in myeloid cells. In this study, we evaluated the expression of IRF4 and IRF8 and the JAK2V617F mutant allele burden in patients with MPNs. Patients with decreased IRF4 expression were correlated with a more developed MPN phenotype in myelofibrosis (MF) and secondary AML (sAML) transformed from MPNs versus essential thrombocythemia (ET). Negative correlations between the JAK2V617F allele burden and the expression of IRF8 (P < 0.05) and IRF4 (P < 0.001) and between white blood cell (WBC) count and IRF4 expression (P < 0.05) were found in ET patients. IRF8 expression was negatively correlated with the JAK2V617F allele burden (P < 0.05) in polycythemia vera patients. Complete response (CR), partial response (PR), and no response (NR) were observed in 67.5%,10%, and 22.5% of ET patients treated with hydroxyurea (HU), respectively, in 12 months. At 3 months, patients in the CR group showed high IRF4 and IRF8 expression compared with patients in the PR and NR groups. In the 12-month therapy period, low IRF4 and IRF8 expression were independently associated with the unfavorable response to HU and high WBC count. Our data indicate that the expression of IRF4 and IRF8 was associated with the MPN phenotype, which may serve as biomarkers for the response to HU in ET.

Level of Microparticles in Patients with Essential Thrombocythemia and Its Relation with JAK2V617F Mutation / 中国实验血液学杂志

OBJECTIVE@#To detect the levels of microparticles (MP) in plasma of patients with esseutial thrombo-cythermia(ET) and analyze the relationship between the JAK2V617F mutant and MP in ET patients.@*METHODS@#The numerical values of MPs were analysed by using flow cytometry. Venous blood of 56 ET patients and 28 healthy persons was collected in the morning and anticoagulated with sodium citrate (1∶9). The RMP, PMP, TF@*RESULTS@#The detection results showed that the MP levels in ET group were higher than those in normal control group: RMP (157.2±304.9/μl vs 21.3±18.4/μl), PMP (1378.9±2454/μl vs 113.8±97.1/μl), TF@*CONCLUSION@#The numerical values of MP detected are more in ET patients than those in healthy controls. The number of MP is higher in patients with thrombus than that without thrombus, so do in patients with splenomegaly and without splenomegaly. Patients with JAK2V617F mutation show higher number of TF

Essential thrombocythemia - a predisponent factor for stroke

SUMMARY The essential thrombocythemia is one of the seven described forms of myeloproliferative neoplasms. It is characterized by megakaryocytic hyperplasia with consequent thrombocytosis maintained in the peripheral blood, favoring the occurrence of thrombo-hemorrhagic phenomena. We present the case of an 81-year-old woman with a history of ischemic stroke in the context of a sustained thrombocytosis, which led to a spinal study and a search for the V617F mutation in the JAK2 gene, which was positive. The patient started cytoreductive therapy with hydroxyurea with favorable current evolution.

Mutational Analysis of SH2B3 in Korean Patients With BCR-ABL1 Negative Myeloproliferative Neoplasm

No abstract available.

JAK2 V617F, MPL, and CALR Mutations in Korean Patients with Essential Thrombocythemia and Primary Myelofibrosis

Mutations in the calreticulin gene, CALR, have recently been discovered in subsets of patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF). We investigated Korean patients with ET and PMF to determine the prevalence, and clinical and laboratory correlations of CALR/JAK2/MPL mutations. Among 84 ET patients, CALR mutations were detected in 23 (27.4%) and were associated with higher platelet counts (P=0.006) and lower leukocyte counts (P=0.035) than the JAK2 V617F mutation. Among 50 PMF patients, CALR mutations were detected in 11 (22.0%) and were also associated with higher platelet counts (P=0.035) and trended to a lower rate of cytogenetic abnormalities (P=0.059) than the JAK2 V617F mutation. By multivariate analysis, triple-negative status was associated with shorter overall survival (HR, 7.0; 95% CI, 1.6-31.1, P=0.01) and leukemia-free survival (HR, 6.3; 95% CI, 1.8-22.0, P=0.004) in patients with PMF. The type 1 mutation was the most common (61.1%) type among all patients with CALR mutations, and tended toward statistical predominance in PMF patients. All 3 mutations were mutually exclusive and were never detected in patients with other myeloid neoplasms showing thrombocytosis. CALR mutations characterize a distinct group of Korean ET and PMF patients. Triple-negative PMF patients in particular have an unfavorable prognosis, which supports the idea that triple-negative PMF is a molecularly high-risk disease.

[Frequency and importance of jak2v617f mutation among Iranian patients with polycythemia vera, essential thrombocythemia and primary myelofibrosis]

Detection of JAK2V617F mutation was widely used in the diagnosis and classification of myeloproliferative neoplasms. In this study, frequency of JAK2V617F mutation among Iranian patients with polycythemia vera [PV], essential thrombocythemia [ET] and primary myelofibrosis [PMF] was studied. In this basic study, blood samples of 174 patients with polycythemia vera [n=57], essential thrombocythemia [n=84] and primary myelofibrosis [n=33] were evaluated for JAK2V617F mutation. Genomic DNA was extracted from peripheral blood. After quality control of extracted DNA, the JAK2-V617F mutation was analyzed using allele-specific PCR. All PCR products were analyzed by polyacrylamide gel [5%] electrophoresis and silver staining. One hundred and eleven out of 174 patients [63.8%] were positive for the presence of the JAK2V617F mutation. Frequency of mutation was 82% [47/57] in PV, 57% [48/84] in ET and 48% [16/33] in PMF. This study showed that detection of JAK2-V617F mutation using allele-specific PCR lead to better diagnosis and treatment of Iranian patients with different MPNs

Philadelphia chromosome positive essential thrombocythemia with dilated cardiomyopathy.

We report here an unusual case of a 30-year old male patient with essential thrombocythemia (ET) and dilated cardiomyopathy, who on further investigation was found to have Philadelphia chromosome positive (Ph+) cells in the bone marrow. The reverse transcriptase-polymerase chain reaction (RT-PCR) test on his peripheral blood leucocytes revealed b2a2 transcript of the bcr-abl fusion gene. Literature shows that the boundary line between Ph+ essential thrombocythemia and chronic myeloid leukemia (CML) is getting blurred day by day. Each one may be a part of the spectrum of a single clonal proliferative disease. Association of dilated cardiomyopathy with ET has not been reported.