The detection and clinical significance of JAK2V617F mutations in myelodysplastic syndrome patients / 中国基层医药

Objective To explore the pathogenesis of myelodysplastic syndrome (MDS)transformation, JAK2V617F mRNA expression levels were compared in peripheral blood of MDS-RA(refractory anemia,RA)and MDS-RAEB(RA with excess blasts,RAEB)patients.Methods JAK2V617F mRNA expression level was detected by fuorescent quantitative polymerase chain reaction(FQ-PCR),and this research reviewed 22 patients diagnosed with MDS,including outpatient and hospitalized patients.20 cases of normal control group were healthy ones.FQ-PCR method was applied to monitor JAK2V617F mRNA expression level in peripheral blood of MDS-RA and MDS-RAEB patients.Results The JAK2V617F gene was not expressed or expressed in healthy subjects,and the copy number was (3 851.96 ±470.46).The patients with MDS-RA(4 631.11 ±3 851.96)was significantly higher than that in healthy subjects(t =3.61,P <0.01);MDS-RAEB patients was (22 545.98 ±11 084.17),and was significantly higher than that in MDS-RA patients(t =4.87,P <0.01).Conclusion JAK2V617F signal transduction can play a role in the pathogenesis and transformation of MDS,and the detection of JAK2-V617F mRNA expression level is use-ful for monitoring progression,judging prognosis and gene regulation therapy of MDS.

Detección de la mutación V617F del genJAK2 mediante análisis de disociación de alta resolución / Detection of V617F mutation of JAK2 gene by high resolution melting / Detecção da mutação V617F do gene JAK2 através da análise de dissociação em alta resolução

La Policitemia Vera (PV), la Trombocitemia Esencial (TE) y la Mielofibrosis Primaria (MP) son neoplasias mieloproliferativas caracterizadas por una proliferación excesiva de una o más líneas mieloides. En el año 2005 se identificó una mutación somática en el gen Janus kinase 2 (JAK2), que resulta en el reemplazo en la proteína de una fenilalanina por una valina en la posición 617 (JAK2 V617F). Esta mutación se encuentra en el 95% de pacientes con PV, y en la mitad de los casos de TE o MP. Se han descripto metodologías que permiten identificar esta mutación: dentro de las más utilizadas se encuentran la ARMS PCR (del inglés Amplification Refractory Mutation System PCR), la secuenciación y recientemente la HRM (High Resolution Melting). En este trabajo se estudió la detección de JAK2 V617F en muestras de pacientes con desórdenes mieloproliferativos mediante HRM, determinando especificidad y sensibilidad de la misma, comparándola con la ARMS PCR y la secuenciación. Los resultados demostraron que la técnica de HRM es superior a la secuenciación y equivalente a la ARMS PCR. Las metodologías sensibles y específicas para la detección de JAK2 V617F, en pacientes con neoplasias mieloproliferativas, son de gran importancia a nivel diagnóstico ya que permiten diferenciar entre desórdenes neoplásicos y condiciones reactivas.

Polycythemia Vera (PV), Essential Thrombocythemia (TE) and Primary Myelofibrosis (MP) are myeloproliferative neoplasias characterized by excessive proliferation of one or more myeloid lines. In 2005, a somatic mutation was identified in the Janus kinase 2 gene (JAK2), resulting in the replacement of a phenylalanine in the protein for a valine at position 617 (JAK2 V617F). This mutation was found in 95% of patients with PV, and in half of the cases of TE or MP. Different methodologies have been described to identify this mutation: the most used are ARMS PCR (Amplification Refractory Mutation System PCR), sequencing and recently HRM (High Resolution Melting). In this work, detection of JAK2 V617F was studied in samples from patients with myeloproliferative disorders using HRM, determining its specificity and sensitivity in comparison with ARMS PCR and sequencing. The results showed that the technique is superior to sequencing and equivalent to ARMS PCR. Sensitive and specific methodologies for the detection of JAK2 V617F in patients with myeloproliferative neoplasias are of great importance at diagnostic level since they can differentiate between neoplastic disorders and reactive conditions.

Policitemia Vera (PV), Trombocitemia Essencial (TE) e Mielofibrose Primária (MP) são neoplasias mieloproliferativas caracterizadas por uma proliferação excessiva de uma ou mais linhas mieloides. Em 2005, uma mutação somática foi identificada no gene Janus quinase 2 (JAK2), resultando na substituição na proteína de uma fenilalanina para uma valina na posição 617 (JAK2 V617F). Esta mutação é encontrada em 95% dos pacientes com policitemia vera, e na metade dos casos de TE ou MP. Foram descritas metodologias para identificar esta mutação: dentre as mais utilizadas estão ARMS PCR (Amplification Refractory Mutation System PCR), sequenciamento e, recentemente, HRM (High Resolution Melting). Neste trabalho a detecção de JAK2 V617F foi estudada em amostras de pacientes com neoplasias mieloproliferativas usando HRM, determinando a sensibilidade e especificidade da mesma, comparando-a com a ARMS PCR e o sequenciamento. Os resultados mostraram que a técnica de HRM é superior ao sequenciamento e equivalente à ARMS PCR. Sensíveis e específicas para a detecção de JAK2 V617F em pacientes com neoplasias mieloproliferativas, as metodologias são de grande importância em nível de diagnóstico, uma vez que permitem diferenciar entre doenças neoplásicas e condições reativas.

Research progress of myeloproliferative disorders: several clinical problems post the JAK2 mutation era / 白血病·淋巴瘤

This critical review was summarized more systematically about the JAK2V617F mutation of related research progress in myeloproliferative disorders (MPD) research fields and the identification of JAK2V617F mutation represents an important advance in our understanding of MPD was agreed. The authors focused on several sensitive problems of post the JAK2 mutation era, and expressed their opinions. The Guideline of the MPD diagnostic criteria recommended by WHO in 2008 was accepted. The authors recommend the MPD, rather than myeloproliferative neoplasm (MPN). The treatment for the MPD (not including the CML) is recommended. Before the effective targeting of JAK2V617F specific inhibitors for the treatment of the MPD, short-term of use hydroxyurea (HU) was suggested to suppress excessive proliferation of bone marrow of MPD and a long course of treatment application of inteferon-α(IFN-α), and low-dose of aspirin in a timely manner were recommended to prevent thrombosis and other complications.

Detection of V617F point mutation of JAK2 gene by real-time PCR in chronic myeloproliferative disease / 白血病·淋巴瘤

Objective To investigate the novel V617F point mutation of JAK2 gene by real-time PGR in the patients with chronic myeloproliferative disease (CMPD) and evaluate its clinical significance. Methods Genomic DNA from bone marrow or peripheral blood mononuclear cells was extracted from 56 patients with CMPD, including 26 cases of polycythemia vera (PV), 24 cases of essential thrombocythemia (ET), 5 cases of chronic idiopathicmyelofibrosis (CIMF) and 1 case of high eosinophilic syndrome (HES). The exon 14 of JAK2 gene which harbourd V617F mutation were screened by real-time PGR. Results JAK2 V617F mutation was measured in 29 of the 56 patients with CMPD. The prevalence of mutation was 65.38 %(17/26) in PV,37.50 % in ET and 60.00 %(3/5) in CIMF. The proportion of mutation in PV, ET and CIMF are respectively 53.85 %(14/26), 29.17 %(7/24), 40.0 %(2/5) in heterozygotes and 11.54 %(3/26), 8.33 %(2/24), 20.00 %(1/5)in homozygotes. JAK2 mutation was negative in one patient with HES. JAK2 V617F allele burden in PV, ET and CIMF are respectively 2.14×102-1.5×107, 9.80×102-4.4×107 and 4.10×103-3.70×106 copies. Conclusion Real-time PCR is a useful tool for pre cisely assess the grade of mutant allele burden as well as to screen JAK2V617F mutation simultaneously, which is simple and convenient to carry out in clinical laboratories for diagnosis and further evaluations of minimal residual disease in CMPD patients.