Genetics and Epigenetics in Myeloid Neoplasms

  • Zamora Group
ICO - German Trias i Pujol

Hematology Laboratory
Molecular Biology Unit
ICO Badalona, Hospital Germans Trias i Pujol 
Ctra. Canyet s/n, 08916 Badalona, Barcelona, Spain

Directions

Summary

Genetic profiling for hematological malignancies means chasing a moving target. Only few years ago, leukaemias were stratified based on karyotye abnormalities. However, in recent years the knowledge of molecular genetics in haematology has increased significantly, something that offers new clinical opportunities. It has now been shown that gene expression, mutations and other genetic and epigenetic abnormalities also have diagnostic, prognostic and therapeutic implications. The aim of our group is to apply our research into three distinct haematological diseases: chronic myelomonocytic leukaemia, myelodisplastic syndromes and myeloproliferative neoplasms (PV, ET, PMF and CML), to finding better tools for diagnosis and prognosis stratification and to achieving an individual targeted therapies (personalized medicine).

Research

We mainly focus our scientific interests on the following research areas:

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic malignancy characterized by features from both myelodysplastic syndromes and myeloproliferative neoplasms with median overall survival of 20 months and 15-30% of progression to acute myeloid leukemia (AML). The WHO and the French-American-Bristish Co-operative Leukaemia Group (FAB) stratifies CMML into two subsets based on blast count (CMML-1 and CMML-2) or leukocyte count (MD-CMML and MP-CMML), respectively. Nowadays there is still doubt whether these variants represent different clinical-biological entities or whether they are expression stages of the same entity. Clonal cytogenetic abnormalities are found in 20-30% of patients. The most frequently mutated genes are TET2, ASXL1, SRSF2, RUNX1 and CBL. The aim of our studies is to characterize 1) type, frequency and prognostic impact of mutations and cytogenetic alterations detected by SNP-arrays in patients with low risk CMML and 2) epigenetic changes (DNA methylation and miRNAs expression). These studies may provide information about the way gene expression deregulation contributes to leukaemogenesis in CMML and it may also help to determinate alterations that correlate with CMML subsets and aggressive variants of this disorder.

The classification and prognosis of the group of diseases termed Myelodisplastic Sindromes (MDS) depend on the blast count, number of cytopenias and cytogenetic data. Chromosomal abnormalities can be only detected in 50% of patients. For this reason, the detection of an aberrant methylation pattern for MDS or a common mutation gene profile may be useful for the diagnosis of this hematologic malignancy. Additionally, the detection of a characteristic methylation pattern or mutations in genes involved in epigenetic regulation could be associated with response to hypomethylating agents, allowing the election of a more personalized and dose-adjusted treatment that adapts to the characteristics of each patient. This knowledge will also contribute to a better understanding of MDS biology, to a better stratification of the prognosis of these patients (especially in the heterogeneous group of normal karyotype), which would also help with the selection of the most appropriate treatment for each of them. The detection of recurrent patterns of methylation will also allow us to identify new tumor suppressor genes.

Chronic myeloid leukemia (CML) is a clonal hematopoietic malignancy characterized by the presence of BCR-ABL fusion gene which give place a protein with a high tyrosine kinase (TK) activity. The first-line treatments for CML are TKI (Ex. Imatinib), which allow the achievement of cytogenetic and molecular response in most of the patients in chronic phase. However, some patients do not respond to this treatment or lose their initial response. The aim of our studies is to determine if we can find any genetic marker at diagnosis of CML that could explain patient’s toxicity to TKI or could differentiate which patients will achieve molecular response (hOCT1 expression, isoforms types, polymorphisms, and mutations). We also want to find a technique with higher sensitivity than QRT-PCR suitable for discontinuation treatment studies (Ex. dPCR)

BCR-ABL negative classic myeloproliferative neoplasms (MPNs) include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). These disorders may undergo phenotypic shifts, and may specifically evolve into secondary myelofibrosis (MF) or acute myeloid leukemia (AML). Discovery of the JAK2V617F mutation in the MPNs has stimulated great interest in the underlying molecular mechanisms and treatment of these diseases. We study several genomic changes (JAK2V617F mutations status and allele burden, SNP arrays and other gene mutational analysis) to try to associate them with cytological subtypes, laboratory parameters, clinical complications and probability of transformation either to MF or to AML.

Collaborations

Dra. Blanca Xicoy
Department of Clínical Hematology (MDS and MPN group). ICO – Germans Trias i Pujol. IJC, Badalona.

Dra. Montse Arnan
Department of Clínical Hematology (MDS and AML group). ICO – Duran i Reynals, Hospitalet.

Dra. Conxa Boqué
Department of Clínical Hematology (MPN group). ICO – Duran i Reynals, Hospitalet.

Dra. Cristalina Fernandez
Department of Clínical Hematology (MPN group). ICO – Josep Trueta, Girona.

Dra. Rosa Coll
Department of Clínical Hematology (MDS and AML group). ICO – Josep Trueta, Girona.

People

NomRol
Lurdes ZamoraZamora L SPrincipal Investigator
Marta CabezónCabezon m 3x3PhD Student
Diana DominguezDominguez 3x3Technician
Silvia MarcéMarcePostdoctoral Investigator
Laura PalomoMPalomo_3XPhD Student
Marisol XandriXandri MPhD Student

Selected publications

Florensa L, Besses C, Zamora L, Bellosillo B, Espinet B, Serrano S, Woessner S, Solé F

Endogenous erythroid and megakaryocytic circulating progenitors, HUMARA clonality assay, and PRV-1 expression are useful tools for diagnosis of polycythemia vera and essential thrombocythemia.

Blood 15 Mar 2004, 103 (6) 2427-8. Més informació
Zamora L, Espinet B, Florensa L, Besses C, Bellosillo B, Solé F

Clonality analysis by HUMARA assay in Spanish females with essential thrombocythemia and polycythemia vera.

Haematologica Feb 2005, 90 (2) 259-61.
Analysis of the human androgen receptor gene (HUMARA) allows clonality to be assessed in essential thrombocythemia (ET) and polycythemia vera (PV). We studied clonality in 44 patients with ET, 18 with PV and in 64 healthy controls. The X-chromosome inactivation pattern was analyzed by HUMARA-polymerase chain reaction on DNA from purified granulocytes, T lymphocytes and the CD3- fraction of mononuclear cells.
Més informació
Zamora L, Xandri M, Garcia O, Marcé S, Xicoy B, Granada I, Navarro JT, Millá F

Association of JAK2 mutation status and cytogenetic abnormalities at diagnosis in myeloproliferative neoplasms and myelodysplastic/myeloproliferative neoplasms.

Am. J. Clin. Pathol. Abr 2012, 137 (4) 677-8. Més informació
Zamora L, Germing U, Cabezón M, Schuler E, Arnan M, Marcé S, Coll R, Pomares H, Brings C, Palomo L, Schmeneau J, Gallardo D, Millá F, Feliu E, Xicoy B

Calreticulin mutations are not present in patients with myeloproliferative chronic myelomonocytic leukemia.

Ann. Hematol. Mai 2015, 94 (5) 869-71. Epub 22 Nov 2014Més informació
Palomo L, Garcia O, Arnan M, Xicoy B, Fuster F, Cabezón M, Coll R, Ademà V, Grau J, Jiménez MJ, Pomares H, Marcé S, Mallo M, Millá F, Alonso E, Sureda A, Gallardo D, Feliu E, Ribera JM, Solé F, Zamora L

Targeted deep sequencing improves outcome stratification in chronic myelomonocytic leukemia with low risk cytogenetic features.

Oncotarget 29 Jul 2016, . Epub 29 Jul 2016
Clonal cytogenetic abnormalities are found in 20-30% of patients with chronic myelomonocytic leukemia (CMML), while gene mutations are present in >90% of cases. Patients with low risk cytogenetic features account for 80% of CMML cases and often fall into the low risk categories of CMML prognostic scoring systems, but the outcome differs considerably among them. We performed targeted deep sequencing of 83 myeloid-related genes in 56 CMML patients with low risk cytogenetic features or uninformative conventional cytogenetics (CC) at diagnosis, with the aim to identify the genetic characteristics of patients with a more aggressive disease. Targeted sequencing was also performed in a subset of these patients at time of acute myeloid leukemia (AML) transformation. Overall, 98% of patients harbored at least one mutation. Mutations in cell signaling genes were acquired at time of AML progression. Mutations in ASXL1, EZH2 and NRAS correlated with higher risk features and shorter overall survival (OS) and progression free survival (PFS). Patients with SRSF2 mutations associated with poorer OS, while absence of TET2 mutations (TET2wt) was predictive of shorter PFS. A decrease in OS and PFS was observed as the number of adverse risk gene mutations (ASXL1, EZH2, NRAS and SRSF2) increased. On multivariate analyses, CMML-specific scoring system (CPSS) and presence of adverse risk gene mutations remained significant for OS, while CPSS and TET2wt were predictive of PFS. These results confirm that mutation analysis can add prognostic value to patients with CMML and low risk cytogenetic features or uninformative CC.
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Current projects

Retrospective study to stablish a relationship between identified polymorphisms and imatinib intolerance or treatment response

Responsable:Lurdes Zamora
Financiadors:
Data d'inici:01/01/2015
Data de finalització:31/12/2015

Patrones de metilación en pacientes con SMD de alto riego y LMA secundaria a SMD tratados con fármacos hipometilantes según el protocolo del Grupo CETLAM SMD-alto riesgo <75 años

Responsable:Lurdes Zamora
Codi:PI11/02519
Financiadors:
Data d'inici:01/01/2012
Data de finalització:31/12/2015

Estudio de los patrones de metilación en pacientes con Síndromes Mielodisplásicos (SMD) y Leucemia Mieloblástica Aguda secundaria a SMD tratados con fármacos hipometilantes versus tratamiento estándar.

Responsable:Lurdes Zamora
Financiadors:
Data d'inici:01/01/2012
Data de finalització:31/12/2015