Inclusion of molecular monitoring (BCR-ABL1) in the treatment of chronic myeloid leukemia in the Brazilian Public Health System (SUS): an urgent need for treatment management

ABSTRACT Introduction: Chronic Myeloid Leukemia (CML) is a myeloproliferative disease that affects mainly adults between 50 and 55 years. In Brazil, information from the Sistema Único de Saúde (SUS) Outpatient Information System indicates that 12,531 patients had the Autorização de Procedimento Ambulatorial (APAC) approved for the CML treatment in 2017. Disease monitoring through molecular response evaluation is critical to the care of CML patients. The quantitative PCR test (real-time polymerase chain reaction) provides adequate evaluation parameters that allow the health professional to intervene at the right moments in order to reduce the chance of progression of the disease, providing the best outcome to the patient, including the possibility of treatment discontinuation for eligible patients. Although the test is included in the Clinical Protocol and Therapeutic Guidelines (PCDT) of CML, it is not possible to monitor the molecular response within SUS since there is no reimbursement for this test. Objective: Obtain expert recommendations on the importance, financing, and reimbursement of molecular monitoring in SUS. Methods: Six CML experts with different perspectives participated in the panel. The discussion was based in the main publications about the quantitative PCR test in CML monitoring. Results: Experts' recommendations: Molecular monitoring should be part of the integral treatment of patients with CML to reduce the chances of disease progression and costs to the health system; The government should put into practice what is provided in the PCDT of Chronic Myeloid Leukemia in Brazil: performing the monitoring of the molecular response via quantitative PCR; The government should create a code with adequate nomenclature and reimbursement value in SIGTAP, so that the test is carried out and covered by the public health network, as it is contained in the PCDT of the disease and the existing APAC does not cover the operational costs for its performance; Patients with chronic phase CML should perform a quantitative PCR every 3 months and, after reaching the MMR, should perform the examination every 6 months, as recommended by international guidelines; Patients should be monitored in reference laboratories that are standardized according to the international scale; The laboratories that are within the reference public centers could absorb all the test demand in Brazil, and other centers could be qualified through an ABHH accreditation; Adequate molecular monitoring may allow some patients to stop taking drugs and selffinancing the molecular test for all SUS patients Conclusion: A solution for the molecular test (BCR-ABL1) funding is urgent to ensure the monitoring of CML patients in SUS. The savings that might be generated with patients that stop taking the medication when adequately monitored may finance the test.

Distribution of ETV6-ABL Fusion Gene in Hematopoietic Cell Populations of Myeloproliferative Neoplasm / 中国实验血液学杂志

OBJECTIVE@#To explore the expression level of ETV6-ABL fusion gene in different cell populations in patients with myeloproliferative neoplasm (MPN) and therapeutic effect of tyrosine kinase inhibitor (TKI).@*METHODS@#A 42-year-old man who presented with fever, marked leukocytosis and chronic myelogenous leukemia (CML) like MPN was reported. ETV6-ABL fusion gene was detected by real-time PCR and confirmed by direct sequencing. ETV6-ABL mRNA expression in each cell population sorted from peripheral blood by flow cytometry was detected by real-time PCR.@*RESULTS@#ETV6-ABL fusion gene was found out in bone marrow cells and confirmed as type A by direct sequencing. ETV6-ABL fusion gene transcript level in polymorphonuclear cells was nearly 3.6-fold relative to that in total cells, which was significantly higher than that in T cell, B cell and monocyte subsets. The complete blood count (CBC) returned to normal level after treatment with imatinib (400 mg) daily for three months. After TKI treatment for 6 months, the ratio of ETV6-ABL/ABL decreased from 174.1% to 1.9%.@*CONCLUSION@#ETV6-ABL fusion gene positive MPN may have a CML clinical presentation and is sensitive to TKI. ETV6-ABL fusion gene is specifically expressed in polymorphonuclear cells.

Mechanism underlying tumorigenesis induced by Bcr-Abl oncogene and A-MuLV virus / 生物工程学报

The Bcr-Abl oncogene is produced by the reciprocal translocation between c-Abl gene on chromosome 9 and the Bcr gene on chromosome 22 in human genome. The encoded Bcr-Abl fusion protein is responsible for the pathogenesis of certain human leukemias. Abelson murine leukemia virus (A-MuLV) is a retrovirus that could lead to transformation of B lymphocyte in mice, and v-Abl is the oncogene of A-MuLV. Abl oncoproteins (such as Bcr-Abl and v-Abl) play critical roles in tumorigenesis of certain cell types. Several signal transduction pathways, including JAK/STAT/Pim, PI3K/AKT/mTOR and RAS/RAF/MEK signaling pathway, are involved in Abl-mediated tumorigenesis. In addition, Abl-mediated tumorigenesis is associated with mutation or abnormal modification of key signal molecules as well as dysregulation of some critical long noncoding RNAs (lncRNAs). Here, we review the molecular mechanisms by which Abl oncogenes activate three major signaling pathways, and provide a scientific basis for therapy of Abl oncoprotein-induced tumors.

Recomendaciones metodológicas para el monitoreo molecular BCR-ABL1 en pacientes con leucemia mieloide crónica por pcr cuantitativa en tiempo real / Guidelines for molecular monitoring of BCR-ABL1 in chronic myeloid leukemia patients by RT-qPCR

Actualmente las guías clínicas para el manejo de pacientes con leucemia mieloide crónica incluyen el monitoreo molecular de BCR-ABL1 por PCR cuantitativa en tiempo real; esta metodología permite definir la respuesta molecular. A pesar de la probada importancia pronóstica de la respuesta molecular, en muchos casos no se tiene en cuenta que la PCR cuantitativa puede producir datos muy variables, que pueden afectar la validez de los resultados, y hacer difícil la comparación entre diferentes laboratorios. Por lo tanto, para un manejo clínico óptimo, es absolutamente necesaria la estandarización de las metodologías de medición de BCR-ABL1. La estrategia para obtener valores de BCR-ABL1 comparables consiste en la adopción de la escala internacional. La conversión a la escala internacional se logra mediante la aplicación de un factor de conversión específico para cada laboratorio; este factor de conversión se puede obtener mediante el uso de calibradores secundarios validados, que hoy se producen en Argentina, en el marco del programa nacional de armonización. Por otra parte, con el objetivo de mitigar las diferencias entre laboratorios y facilitar criterios uniformes en la interpretación de los resultados y presentación de los informes, decidimos preparar estas guías de laboratorio. Esto permitirá además a los laboratorios poder evaluar su calidad de trabajo, tarea muy importante, en particular para aquellos centros más aislados, que no tienen fácil acceso a costosos kits comerciales o programas internacionales de intercambio de muestras.

Current clinical guidelines for managing chronic myeloid leukemia include molecular monitoring of BCR-ABL1 transcript quantitative reverse-transcription PCR. Despite the proven prognostic significance of molecular response, it is not widely appreciated that quantitative reverse-transcription PCR potentially produces highly variable data, which may affect the validity of results, making comparability between different laboratories difficult. Therefore, standardized reporting of BCR-ABL1 measurements is needed for optimal clinical management. An approach to achieve comparable BCR-ABL1 values is the use of an international reporting scale. Conversion to the international scale is achieved by the application of laboratory specific conversion factor that is obtained by using validated secondary reference calibrators. Moreover, with the aim to mitigate the interlaboratory imprecision of quantitative BCR-ABL1 measurements and to facilitate local laboratory results interpretation and reporting, we decide to prepare laboratory guidelines that will further facilitate interlaboratory comparative studies and independent quality-assessment programs, which are of paramount importance for worldwide standardization of BCR-ABL1 monitoring results, in particular for those most isolated laboratories, with not easy access to commercial kits or sample interchange programs.

Clinical characteristics of childhood leukemia with EVI1 gene and BCR/ABL gene co-expression / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the clinical characteristics of ecotopic viral integration site-1 (EVI1) and BCR/ABL positive childhood leukemia.</p><p><b>METHODS</b>Clinical data of four children with EVI1 and BCR/ABL positive leukemia and eight children with BCR/ABL positive but EVI1 negative chronic myeloid leukemia (CML) were retrospectively analyzed.</p><p><b>RESULTS</b>In the four children with EVI1 and BCR/ABL positive leukemia, two were initially diagnosed with chronic phase of CML, one with accelerated phase of CML and one with high-risk acute lymphoblastic leukemia (ALL). There were no significant differences in clinical characteristics at diagnosis between the patients with EVI1 and BCR/ABL positive leukemia and BCR/ABL positive but EVI1 negative leukemia. CD33 and CD38 were highly expressed and t(9;22) abnormality was present in all patients with EVI1 and BCR/ABL positive leukemia. Two of the 3 children with EVI1 and BCR/ABL positive CML achieved complete remission one or three months after treatment. Acquired negative status conversion occurred for EVI1 but not BCR/ABL in one CML case. The 3 children with EVI1 and BCR/ABL positive CML survived 20, 13 and 14 months, respectively, without recurrence. The child with EVI1 and BCR/ABL positive ALL failed to achieve complete remission after the first course of treatment and discontinued further treatment.</p><p><b>CONCLUSIONS</b>Co-expression of EVI1 and BCR/ABL fusion gene can be found in childhood CML and ALL. The relatively rare leukemia has not significant difference respect to clinical characteristics. Prognosis of the disease needs to be determined by clinical studies with a larger sample size.</p>

Frequency of Janus associated kinase 2 [JAK2] mutation in patients of BCR-ABL negative myeloproliferative neoplasms

To determine the frequency of Janus associated kinase 2 mutation in the patients of BCR-ABL negative classical myeloproliferative neoplasms. Cross-sectional descriptive study. Molecular Department of Haematology, Armed Forces Institute of Pathology [AFIP], Rawalpindi from Jul 2011 to Jul 2012. Ninety three consecutive patients of Polycythaemia vera [PV], Essential thrombocythaemia [ET] and Idiopathic myelofibrosis [IMF] diagnosed by the conventional haematological criteria were included in the study. All patients were screened for G-T point mutation [V617F] in the JAK2 gene on chromosome 9 by an allele specific PCR. Out of the 93 myeloproliferative neoplasm [MPN] patients, 33[35%] had polycythaemia vera, 36[39%] had essential thrombocythaemia and 24[26%] had idiopathic myelofibrosis. JAK2 mutation was seen in 64/93 [69%] patients including 33/33[100%] in PV, 19/36[52.6%] in ET and 12/24[50%] in IMF. Classical myeloproliferative neoplasms are an important group of heamatological disorder in our country. JAK2 gene mutation is seen in significant proportion of these disorders [69%]. JAK2 mutation analysis can be used to differentiate between polycythemia vera and secondary polycythemia in most cases with near certainty, where it was found in 100% of the cases

Effect of dihydroartemisinin on the expression of BCR/ABL fusion gene in leukemia K562 cells / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the effect of dihydroartemisinin (DHA) on the BCR/ABL fusion gene in leukemia K562 cell.</p><p><b>METHODS</b>K562 cells were cultured in vitro. The rate of proliferation inhibition of cells treated with various concentrations of DHA were determined by using [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) method. Expression of BCR/ABL fusion gene was analyzed by reverse transcription(RT-PCR) before and after DHA treatment. Apoptosis of K562 cells was detected by flow cytometry.</p><p><b>RESULTS</b>The growth of K562 cells was inhibited when the concentrations of DHA were 10-160 umol/L. With the added dose of DHA, the growth inhibition was remarkable, with the rate of inhibition risen from 52.76% to 94.65%. The expression of BCR/ABL fusion gene, as detected by RT-PCR after incubating the K562 cells with 20 umol/L DHA, measured as ΔCt = 4.45 ± 0.25 after 12 h and ΔCt = 5.23 ± 0.21 after 24 h, which was significantly lower compared with that of the control ( ΔCt = 4.23 ± 0.21, P < 0.05).</p><p><b>CONCLUSION</b>DHA can inhibit the proliferation of leukemia K562 cells and facilitate the induction of apoptosis by downregulating the expression of BCR/ABL fusion gene.</p>

ALL-2005 protocol experience in the therapy of children and adolescents over 10 years of age with acute lymphoblastic leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the incidence, clinical characteristics and prognosis of children and adolescents over 10 years of age with acute lymphoblastic leukemia (ALL).</p><p><b>METHODS</b>From May 1, 2005 to April 30, 2009, 67 newly diagnosed ALL children and adolescents over 10 years of age were enrolled in protocol of ALL-2005. All of the clinical characteristics of the patients were analyzed. The statistics was done by SPSS 13.0.</p><p><b>RESULTS</b>There were 40 males (59.7%) and 27 females (40.3%). The mean age at diagnosis was 12.3 ± 1.7 (10.0 to 17.8) years with median age of 12.2 years. Of 67 patients, 48 were in medium risk group, and 19 in high risk group. During induction therapy, 83.6% and 86.6% patients had good response to prednisone and bone marrow blasts ≤ 5% at day 19, respectively. The overall hematologic response rate in these 67 patients was 88.1% (59) in complete remission (CR) after induction therapy, 15 patients relapsed with mean continuous CR period of (14.9 ± 9.9) months. The five-year event-free survivals (EFS) and overall survivals (OS) were (64.4 ± 6.3)% and (74.1 ± 6.1)%, respectively. According to univariate analysis, elevated serum ferritin, bcr-abl translocation, poor response to prednisone, high bone marrow blasts at day 19 or after induction therapy, and high minimal residual disease (MRD) after induction therapy increased risk for recurrence. Multivariate analysis indicated that high MRD after induction therapy was associated with recurrence (RR = 2.20, 95%CI 1.26 - 3.84, P < 0.01).</p><p><b>CONCLUSION</b>Survival has improved for children and adolescents with ALL by ALL-2005 protocol. Analysis of serum ferritin and bcr-abl translocation at diagnosis, early responses to treatment and MRD detection during therapy are powerful prognostic indicators.</p>

Detection of BCR/ABL fusion gene by fluorescence in situ hybridization and its clinical application / 中国实验血液学杂志

This study was aimed to investigate the clinical value of detecting BCR/ABL fusion gene by fluorescence in situ hybridization (FISH). The conventional cytogenetic test and detection of BCR/ABL fusion gene by FISH for bone marrow of patients with newly diagnosed chronic myeloproliferative disease or myelodysplastic and myeloproliferative disorders, acute lymphocytic leukemia and chronic myelogenous leukemia (CML) after allogeneic hematopoietic stem cell transplantation were carried out. The results showed that (1) out of 46 newly diagnosed as chronic myeloproliferative disease or myelodysplastic and myeloproliferative disorders, 22 cases were diagnosed as CML, the FISH detection showed all positive (100%), while cytogenetic test showed 86.4% (19/22) positive, in the other 24 patients who were diagnosed as other chronic myeloproliferative disease or myelodysplastic and myeloproliferative disorders, BCR/ABL fusion gene all were be detected as negative 100% by FISH, while the cytogenetic test of bone marrow in 3 cases supported the diagnosis of CML, and the diagnosis of myelodysplastic disorder in 1 case; (2) in 3 out of 7 acute lymphocytic leukemia cases the BCR/ABL fusion gene could not be detected by FISH; (3) the BCR/ABL fusion gene could be detected by FISH in 2 cases of CML received allogeneic hematopoietic stem cell transplantation, with abnormal threshold 6.5% and 1.2% respectively. It is concluded that the detection of BCR/ABL fusion gene by FISH is sensitive and reliable, which is very important for the diagnosis and differential diagnosis of chronic myeloproliferative disorders, myelodysplastic and myeloproliferative disease, as well as definite diagnosis of Ph(+) acute lymphoblastic leukemia. This method also has an important significance for monitor of minimal residual disease in CML patients received allogeneic hematopoietic stem cell transplantation.

Dual-color/dual-fusion interphase fluorescence in situ hybridization probe for monitoring tumor load during imatinib therapy for chronic myeloid leukemia / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the sensitivity and specificity of dual-color and dual-fusion interphase fluorescence in situ hybridization (D-FISH) in determining the tumor load in patients with chronic myeloid leukemia (CML) receiving imatinib therapy.</p><p><b>METHODS</b>The BCR-ABL fusion gene was detected by FISH in 24 cases of chronic myeloid leukemia treated with imatinib. The sensitivity and specificity of D-FISH were compared with those of single-fusion FISH (S-FISH) and RT-PCR.</p><p><b>RESULTS</b>D-FISH was more sensitive and specific than S-FISH. In normal control subjects, the cutoff rates of D-FISH and S-FISH were 0.73% and 6.24%, respectively, showing a significant difference between them. In 24 CML cases receiving imatinib treatment, the positivity rates of S-FISH and D-FISH were 7/24 (29.2%) and 13/24 (54.2%), respectively. The results of D-FISH had a high correlation to that of RT-PCR.</p><p><b>CONCLUSION</b>With lower false positive and false negative results, D-FISH can be used as a sensitive and specific method for monitoring the changes of the tumor load in CML patients during imatinib treatment.</p>

[Evaluation of Morpholino antisense oligos' role on BCR-ABL gene silencing in the K562 cell line]

Chronic myeloid leukemia [CML] develops when a hematopoietic stem cell acquires the BCR/ABL fusion gene. This causes these transformed hematopoietic cells to have a greater than normal proliferation rate. Scientists attempt to improve the CML treatment process by silencing the BCR/ABL oncogene. In this work, we used morpholino antisense oligos to silence the BCR/ABL oncogene. In this study, the K562 was used as a BCR/ABL fusion-gene positive cell line and the Jurkat cell line as a control. We explored the inhibiting capacity of morpholino antisense oligos in the the expression of the BCR/ABL oncogene and studied their p210 BCR/ABL suppression, inhibition of cell proliferation and stimulation of apoptosis in the K562 cells after 24 and 48 hours. Endo-Porter was used for delivery of morpholino antisense oligos into cell cytosols. Meanwhile, flow cytometric analysis was performed in order to determine the appropriate concentration of morpholino antisense oligos. Prolonged exposure of the K562 cell line to the morpholino antisense oligos targeted against the BCR-ABL gene showed proliferation inhibition as its main feature. After western blotting, we found that complete silencing of BCR/ABL was achieved, but flow cytometric analysis showed no broad apoptosis. The results indicate that the Morpholino antisense oligo is able to inhibit p210 BCR/ABL; however, it cannot induce broad apoptosis due to co-silencing of BCR

Clinical characteristics and outcomes of 59 patients with acute lymphoblastic leukemia positive for BCR/ABL / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the clinical characteristics and outcomes of BCR/ABL-positive acute lymphoblastic leukemia (BCR/ABL360888725-ALL) and screen the prognostic factors for BCR/ABL360888725-ALL.</p><p><b>METHODS</b>From January 2001 to May 2008, 59 patients (median age of 32 years ranging from 3 to 69 years) with the diagnosis of BCR/ABL360888725-ALL by fluorescence in situ hybridization received induction chemotherapy with VDLP-/+Ara-C regimen. The patients who failed to respond to the chemotherapy received subsequent consolidation chemotherapy with imatinib (400-800 mg/day) (17 cases) or allogeneic hematopoietic stem cell transplantation (allo-HSCT) (16 cases).</p><p><b>RESULTS</b>Of the 59 patients, 32 (58.3%) achieved complete remission (CR) after the first induction cycle. In patients with peripheral white blood cell (WBC) count <30=10(9)/L, 30-99.9(9)/L and > or =100(9)/L, the CR rates were 75.0% (18/24), 56.3% (9/15) and 26.3% (5/19) (P=0.006), and the overall survival probability of 2 years ( OSs of 2-yrs) was 24.7%, 22.5% and 21.1%, respectively (P=0.180). According to the FAB classification, 56 cases were divided into L1, L2 and biphenotypic acute leukemia (BAL) subgroups, and their CR rates were 66.7% (6/9), 63.2% (24/38) and 22.2% (2/9) (P=0.029), with OSs of 2-yrs of 22.2%, 27.0% and 22.0%, respectively (P=0.623). In terms of immunophenotype grouping by EGIL, the patients with ALL, myeloid antigen-positive ALL and BAL had CR rates of 61.1% (11/18), 60.6% (20/33) and 12.5% (1/8) (P=0.039), and the OSs of 2-yrs of 22.7%, 21.0% and 18.8%, respectively (P=0.643). In 55 patients with known karyotype, the CR rates were 71.4%(5/7), 70.8% (17/24) and 37.5% (9/24) in normal, sole t(9;22) abnormality, t(9;22) with additional abnormalities groups (P=0.046), with the OSs of 2-yrs of 42.9%, 34.0% and 7.3%, respectively (P=0.000). The patients complicated by septicemia had significantly lower OSs of 2-yrs than those without septicemia (0% vs 38.8%, P=0.005). The OSs of 2-yrs were significantly higher in patients with consolidation chemotherapy with imatinib than those without (48.0% vs 11.2%, P=0.001), and allo-HSCT was associated with significantly higher OSs of 2-yrs than exclusive chemotherapy (54.2% and 8.5%, P=0.000).</p><p><b>CONCLUSION</b>BCR/ABL360888725-ALL with WBC> or =100 x 10(9)/L, presence of BAL diagnosed by FAB or FACM, t(9;22) with additional chromosome abnormalities all adversely affect the treatment results, and additional chromosome abnormalities and septicemia are associated with lower OSs of 2-yrs. Imatinib treatment and allo-HSCT can both improve the OSs of 2-yrs of the patients with BCR/ABL(+)-ALL.</p>

Detección molecular del gen BCR-ABL por RT-PCR en niños costarricenses con leucemia

Molecular detection of the BCR-ABL gen by RT-PCR In Costa Rican children with leukemia. Many leukemias could have chromosomic translocations and according to the transcripts formed by the genes involved, the patients present an specific phenotype of the leukemia. We show the first results of the investigation of the gen BCR-ABL using RT-PCR, in order to look for the t(9;22)(q34;q11) in pediatric leukemic children. We studied in total 55 patients, 6 (10.9%) of them were positive for that translocation. Two (3.63%) of the positive children had ALL and the other 4 (7.27%) presented CML, the genotyping analysis of the transcript was studied in these children. With the introduction of this methodology as part of the routine studies, the leukemic children could get in the future an specific diagnosis, that will be important to classify them in prognostic categories and to improve the detection of minimal residual disease. Rev. Biol. Trop. 56 (4): 1613-1618. Epub 2008 December 12.

Muchas leucemias pueden presentar traslocaciones cromosómicas, las cuales, de acuerdo a los transcriptos formados por los genes involucrados, originará un fenotipo leucémica variable. En este trabajo se muestran los primeros resultados de pacientes pediátricos con leucemia, a los cuales se les hizo el estudio molecular por RT-PCR y el genotipaje para el gen BCR-ABL producto de la t(9;22)(q34;q11). De las 55 muestras estudiadas, 6 (10.9%) fueron positivas para el transcripto mencionado. De las 6 positivas, 2(3.63%) de esos pacientes tenían LLA y 4 (7.27%) eran LMC. La introducción de esta metodología en el manejo rutinario de los niños con leucemia, servirá para establecer un diagnóstico más preciso, un pronóstico más certero y un seguimiento adecuado de la enfermedad mínima residual.

Prognostic factors for childhood acute non-mature B-lymphoblastic leukemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the prognostic factors for events-free survival (EFS) in children with acute non-mature B-lymphoblastic leukemia.</p><p><b>METHODS</b>One hundred and sixty-one children with newly diagnosed acute non-mature B-lymphoblastic leukemia received the ALL-XH-99 protocol treatment. Their medical data, including clinical, biological and molecule features, early responses to treatment (bone marrow evaluation on the 19th day of induction therapy), minimal residual disease (MRD) in bone marrow after remission induction therapy, the risk grade of disease before the beginning of chemotherapy and the outcome, were retrospectively studied.</p><p><b>RESULTS</b>Univariable analysis indicated that the gender and P170 levels before therapy had no effect on the outcome. Age, initial white blood cell count (WBC), prednisone response, early response to treatment, fusion genes (BCR/ABL or MLL/AF4) and MRD level were significantly related to the EFS (P<0.01). Immunophenotype, myeloid-associated antigen and the risk grade of disease were also related to the EFS (P<0.05). Multivariable analysis showed that WBC >or=50 x 10(9)/L, Cmu positive, BCR/ABL or MLL/AF4 positive and MRD positive (>or=0.01%) were risk factors for the poor prognosis (P<0.01). The early response to treatment was important to modify the therapy protocol.</p><p><b>CONCLUSIONS</b>WBC >or=50 x 10(9)/L, Cmu positive, BCR/ABL or MLL/AF4 positive and MRD positive have important prognostic values in childhood acute non-mature B-lymphoblastic leukemia. Early response to treatment is an important index for modifying the chemotherapy protocol.</p>

Detection of bcr/abl fusion gene changes in patients with chronic myeloid leukemia after allo-HSCT by real-time quantitative reverse transcription polymerase chain reaction and its significance / 中国实验血液学杂志

This study was aimed to detect the changes of bcr/able gene level in ph+ CML patients at different stages after allo-HSCT by real-time quantitative PCR and to evaluate the significance of this detection. The serial detection of bcr/abl fusion gene levels in 21 cases of CML treated with allo-HSCT was performed by RQ-PCR. The results showed that the bcr/able fusion gene could not be detected in 7 out 21 CML cases with positive fusion gene after allo-HSCT, while the bcr/abl fusion gene of different levels could be detected in 14 cases within 1-6 months. Dynamic detection indicated that the bcr/abl fusion gene levels in 9 cases were lower with relative value 0.0074%-0.088% and then could not be detected within 3-7 months after allo-HSCT. The bcr/abl fusion gene levels in 5 cases diagnosed as molecular relapse were between 0.077%-75%. The bcr/abl fusion gene levels in 1 out of 5 cases were 0.95%, 1.5%, and 0.16% in month 1, 2 and 3, respectively, and turned to negative in the month 4 without any treatment after allo-HSCT. 2 cases received the donor peripheral blood stem cell infusion, and then their bcr/abl mRNA levels could not be detected in bone marrow. Another 2 cases developed to the hematologic relapse, 1 out of 2 cases reached CR again after infusion of donor peripheral blood stem cells and chemotherapy, the other one died. It is concluded that serial quantifications of bcr/abl mRNA levels by RQ-PCR are reliable and can be used to detect the MRD, to monitor the outcome and to predict the relapse.

Research advance on molecular genetics of CML blast crisis / 中国实验血液学杂志

Philadelphia (Ph) chromosome at (9; 22) reciprocal chromosomal translocation producing BCR-ABL fusion gene, emerges in almost all patients with chronic myeloid leukemia (CML). The protein product of BCR-ABL is a constitutively active tyrosine kinase that drives the abnormal proliferation of CML cells. Blast crisis (BC) is the terminal phase of CML, which is often associated with additional chromosomal and molecular secondary changes. Although the mechanisms responsible for transition of CML chronic phase (CP) into BC remain poorly understood, ample evidence suggests that it depends on synergy of BCR/ABL with other genes dysregulated during disease progression, and signaling pathways are abnormally activated by BCR/ABL. With the application of imatinib, a ABL-specific tyrosine kinase inhibitor, its remarkable therapeutic effects suggest that blast crisis transition will be postponed in most patients with CML. Rate of cumulative best response in CML-CP patients from the IRIS trial after 5 years are 98% for complete hematologic response, 92% for major cytogenetic response and 87% for complete cytogenetic response. However, a minority of CML-CP patients and most patients in progression either fail or respond suboptimally to imatinib. There are many distinct patterns of resistance, and ABL kinase mutations is a common finding associated with clinical resistance. Dasatinib and nilotinib can restore hematologic and cytogenetic remission in the majority of patients with primary failure or acquired resistance in chronic phase. This review illustrates the molecular mechanisms underlying transition to CML-BC, also addresses oneself to how and why imatinib resistance occurs.

Detection of PML/RARalpha gene transcripts in 46 newly diagnosed acute promyelocytic leukemia patients by real-time quantitative reverse-transcription polymerase chain reaction / 中国实验血液学杂志

In order to explore the application of real-time quantitative reverse-transcription polymerase chain reaction (Q-PCR) for detecting PML/RARalpha gene transcripts in patients with acute promyelocytic leukemia (APL), the bone marrow samples from 46 newly diagnosed APL patients were collected for analysis. Three plasmids containing cDNA fragments of the bcr1-, bcr3-form PML/RARalpha and ABL control gene were constructed respectively. The ABI Prism 7500 Sequence Detection System using Taqman fluorogenic probes was used to quantify target gene. PML/RARalpha mRNA was detected by Q-PCR in 46 APL patients and 40 non-APL patients. The normalized quotient (NQ) of PML/RARalpha mRNA was calculated as followings: NQ = PML/RARalpha mRNA copy numbers/ABL mRNA copy numbers. Immunophenotype of acute promyelocytic leukemia was determined by four-color flow cytometry. The results showed that the coefficients of variation (CV) of inter-day assay and intra-day assay by using Q-PCR were 1.58% and 0.88% respectively. Q-PCR could detect reproducibly 5 copies of target gene per 100 ng RNA and no pseudopositive results were found. The median NQ of PML/RARalpha mRNA was 0.450 (0.084 - 1.082) in 46 APL patients. There was no indication of any correlation of PML/RARalpha mRNA type with age, sex, hemoglobin, platelet count, percentage of promyelocytes in bone marrow detected by morphology or flow cytometry, PML/RARalpha NQ, or signs of clinically diagnosed coagulation/bleeding disorders. Compared with bcr1-form cases, bcr3-form cases had more M(3v) phenotype (42.9% vs 9.4%, P = 0.015) and higher WBC count (9.35 x 10(9)/L vs 2.15 x 10(9)/L, P = 0.038). APL cells could be classified into large side scatter population (L-SSC) and non-large side scatter population (NL-SSC) in CD45/SSC histogram of flow cytometry. 87.50% patients with bcr1-form showed L-SSC phenotype and 64.29% patients with bcr3-form showed NL-SSC phenotype. It is concluded that a sensitive Q-PCR method is established. The median NQ of PML/RARalpha mRNA was 0.450 in newly diagnosed APL patients. There was no significant difference about PML/RARalpha mRNA expression of both bcr3-form and bcr1-form APL patients. Type of PML/RARalpha transcripts is related with the morphology and immunophenotype.