BJH - volume 11, issue 6, october 2020
L. De Smaele , M. Hofmans MD, T. Lammens PhD, A. Van Damme MD, PhD, J. van der Werff ten Bosch MD, PhD, A. Ferster MD, PhD, J. Verlooy MD, C. Chantrain , J. Philippé MD, PhD, N. Van Roy PhD, P. De Paepe MD, PhD, V. Labarque MD, PhD, B. De Moerloose MD, PhD
Childhood myelodysplastic syndrome (MDS) and juvenile myelomonocytic leukaemia (JMML) are very rare clonal stem cell disorders of early childhood. Paediatric MDS can be further subdivided in refractory cytopenia of childhood (RCC) and high grade MDS, in case of excess blasts. Given their rarity, little is known about the epidemiology of these diseases in Belgium. The aim of this study is to investigate the incidence, characteristics, treatment and prognosis of paediatric MDS and JMML in Belgium. Prospectively collected data of 56 Belgian patients with MDS and JMML were enrolled in the study, of which 41 (73%) with MDS, eleven with JMML (20%) and four (7%) with Noonan syndrome associated myeloproliferative disorder. The incidence rates of MDS and JMML in Belgium were 1.5 and 0.4 per million children per year respectively, with a median age of diagnosis of 9.3 years for RCC, 9.5 years for high grade MDS and 2.6 years for JMML. Monosomy 7 was the most common cytogenetic abnormality and could particularly be found in high grade MDS (33%) and JMML (45%). RCC treatment consisted of immunosuppressive therapy (IST) and haematopoietic stem cell transplantation (HSCT), but in high grade MDS and JMML only HSCT was a valid treatment option. Overall survival was significantly lower in high grade MDS (45.0%) compared to JMML (79.5%) and RCC (80.6%) (log-rank p-value = 0.038), whereas event-free survival (EFS) was comparably low in high grade MDS and JMML (46.7% and 58.4% respectively) due to a high cumulative incidence of relapse (CIR) of 33% and 29.9%, respectively. Outcome was best for RCC patients with highest EFS (76.3%; 57.1% if IST failure was considered as event) and lowest CIR (9.3%). This study highlights that paediatric MDS and JMML are very rare disorders with associated morbidity and mortality, especially in high grade MDS and JMML. Considering the high relapse risk in high grade MDS and JMML, new therapeutic options are required.
(BELG J HEMATOL 2020;11(6):233-9)Read more
BJH - volume 11, issue 6, october 2020
B. Depreter PhD, PharmD, B. De Moerloose MD, PhD, J. Philippé MD, PhD, T. Lammens PhD
Ample evidence was provided these past decades that leukaemic stem cells (LSC) play a role in the outcome of adult and paediatric acute myeloid leukaemia (AML) patients. Although it is generally accepted that the CD34+/ CD38- compartment is most LSC-enriched, novel data have emerged illustrating a distinct biology between CD34+ and CD34- AML. In this review, we discuss the main LSC phenotypes in CD34+ and CD34- AML , as they are of utmost importance for the development of broadly applicable LSC-targeted strategies. The leukaemia-initiating capacity of these cells upon xenografting is still considered to be the gold standard for LSC detection. However, more feasible techniques have been researched to allow the implementation of LSC measurements into clinical practice. Here, we summarise the current state-of-the-art methodologies using flow cytometry and molecular detection, and emphasise their relevance in terms of prognosis and targeted drug therapy.
(BELG J HEMATOL 2020;11(6):246-52)Read more
BJH - volume 11, issue 2, march 2020
M. Hofmans MD, T. Lammens PhD, B. De Moerloose MD, PhD
Juvenile myelomonocytic leukaemia is a heterogeneous disease caused by constitutional activation of the Ras signal transduction pathway. The clinical course of the disease is variable and non-specific. In the majority of patients prompt hematopoietic stem cell transplantation is necessary for long-term survival, whereas in a minority the disease will resolve without treatment. In more than 90% of the patients, mutations in one or more of the following genes can be found (somatic NRAS, KRAS and PTPN11, germline NF1 and CBL). However, these canonical mutations are insufficient to explain the phenotypic heterogeneity of this disease. More recently, secondary mutations, non-coding RNA expression, and genomic DNA methylation have led to a better understanding of the pathobiology of the disease, and shown to play a role in the classification and prognostication of this rare disease. In addition, this novel information has been crucial for novel drug development and introduction of novel patient-tailored therapies, which are currently being tested in vitro or in vivo in clinical trials.
(BELG J HEMATOL 2020;11(2):49–55)
BJH - volume 9, issue 2, march 2018
B. De Moerloose MD, PhD, E. Nauwynck MD, K. Arts MD, L. Willems MD, PhD, V. Labarque MD, PhD, T. Lammens PhD, A. Uyttebroeck MD, PhD
Infant leukaemia is a rare disease but the 3rd most frequent malignancy in this age group. Both acute lymphoblastic leukaemia and acute myeloid leukaemia in the first year of life have particular clinical and biological characteristics such as B-cell phenotype with co-expression of myeloid markers in acute lymphoblastic leukaemia, FAB M5 or M7 in acute myeloid leukaemia, the presence of extramedullary symptoms and a high frequency of KMT2A rearrangements. Survival rates for infant acute leukaemia are worse than for older children. In this study, the characteristics and outcome of 50 infants with acute lymphoblastic leukaemia and acute myeloid leukaemia treated at the University Hospitals of Ghent and Leuven between 1989 and 2015 were studied and correlated with literature data. With event-free survival and overall survival rates of 44% and 52% for the entire cohort, the outcome of these patients was comparable to those in published clinical trials. In general, the event-free survival and overall survival was superior in acute myeloid leukaemia compared to acute lymphoblastic leukaemia infants and not influenced by age (< or ≥6 months), white blood cell count at diagnosis or presence of a KMT2A rearrangement. For future trials in infant leukaemia, the high number of early deaths, toxic deaths and relapses remain the most challenging problems.
(BELG J HEMATOL 2018;9(2):57–63.)Read more
BJH - 2018, issue Abstract Book BHS, february 2018
M. Hofmans MD, T. Lammens PhD, S. Bresolin , H. Cavé , C. Flotho , H. Hasle , H. Helsmoortel PhD, M. Van den Heuvel-Eibrink , C. Niemeyer , J. Stary , N. Van Roy PhD, P. Van Vlierberghe PhD, J. Philippé MD, PhD, B. De Moerloose MD, PhD
BJH - volume 8, issue 5, september 2017
F. Ghazavi PhD, T. Lammens PhD, P. Van Vlierberghe PhD, B. De Moerloose MD, PhD
Acute lymphoblastic leukaemia, a clinically and biologically heterogeneous disease, represents the most common malignant disease in childhood. Approximately 20–25% of B-cell precursor acute lymphoblastic leukaemia in childhood carry the cryptic chromosomal translocation t(12;21)(p13;q22). This translocation combines two transcription factors and essential regulators of normal haematopoiesis, ETV6 and RUNX1, into the fusion oncogene ETV6/RUNX1 (formerly known as TEL/AML1). Recent studies in various animal models have strengthened the view that ETV6/RUNX1-positive cells give rise to pre-leukemic clones with a differentiation block in the pro/pre-B stage of B-cell development that, after acquisition of additional mutations, may transform into full malignancy. Despite the favourable prognostic parameters of this B-cell precursor acute lymphoblastic leukaemia subgroup, relapse and resistance to chemotherapeutics do occur and increased knowledge of the molecular mechanisms underlying ETV6/RUNX1-driven leukaemia is essential to develop novel therapeutic strategies to selectively target ETV6/RUNX1-positive leukaemia. In this manuscript, an overview of the most recent genetic insights in ETV6/RUNX1-positive B-cell precursor acute lymphoblastic leukaemia is given.
(BELG J HEMATOL 2017;8(5):179–84)Read more
BJH - volume 8, issue 5, september 2017
H. Helsmoortel PhD, T. Lammens PhD, P. Van Vlierberghe PhD, B. De Moerloose MD, PhD
Juvenile myelomonocytic leukaemia is a rare and aggressive blood cancer occurring in early childhood. Research in the past decades mainly focused on identifying aberrations at the DNA level. Although our molecular knowledge about juvenile myelomonocytic leukaemia biology has steadily increased over the last years, haematopoietic stem cell transplantation is currently the only curative option. Unfortunately, the relapse rate after stem cell transplantation remains high and almost half of the children do not survive the disease, indicating that new therapeutic strategies are urgently required. To further elucidate the biology of the disease, we investigated gene expression levels of both coding and non-coding RNA molecules. This led to the identification of LIN28B and its co-regulated genes as central players in juvenile myelomonocytic leukaemia biology and opens the door for the development of new targeted therapeutics.
(BELG J HEMATOL 2017;8(5):198–200)Read more