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Kratz C.P.,Hannover Medical School | Stanulla M.,Hannover Medical School | Cave H.,Assistance Publique des Hopitaux de Paris AP HP | Cave H.,University Paris Diderot
European Journal of Medical Genetics | Year: 2016

Environmental causes of childhood acute lymphoblastic leukemia (ALL) remain largely undiscovered. In contrast, multiple germline ALL risk variants have been identified in the recent years. Apart from the low-risk common ALL risk alleles identified through genome wide association studies, rare germline mutations that cause cancer prone syndromes have been found to be associated with an increased risk of developing ALL. Here, we review the germline genetic changes known to be associated with ALL. © 2015 Elsevier Masson SAS. Source

Mulero-Navarro S.,Mount Sinai School of Medicine | Sevilla A.,Mount Sinai School of Medicine | Roman A.C.,CSIC - Institute of Refrigeration | Lee D.-F.,Mount Sinai School of Medicine | And 25 more authors.
Cell Reports | Year: 2015

Somatic PTPN11 mutations cause juvenile myelomonocytic leukemia (JMML). Germline PTPN11 defects cause Noonan syndrome (NS), and specific inherited mutations cause NS/JMML. Here, we report that hematopoietic cells differentiated from human induced pluripotent stem cells (hiPSCs) harboring NS/JMML-causing PTPN11 mutations recapitulated JMML features. hiPSC-derived NS/JMML myeloid cells exhibited increased signaling through STAT5 and upregulation of miR-223 and miR-15a. Similarly, miR-223 and miR-15a were upregulated in 11/19 JMML bone marrow mononuclear cells harboring PTPN11 mutations, but not those without PTPN11 defects. Reducing miR-223's function in NS/JMML hiPSCs normalized myelogenesis. MicroRNA target gene expression levels were reduced in hiPSC-derived myeloid cells as well as in JMML cells with PTPN11 mutations. Thus, studying an inherited human cancer syndrome with hiPSCs illuminated early oncogenesis prior to the accumulation of secondary genomic alterations, enabling us to discover microRNA dysregulation, establishing a genotype-phenotype association for JMML and providing therapeutic targets. Using hiPSCs, Mulero-Navarro et al. recapitulate the principal features of JMML and show dysregulation in myeloid cells in the context of NS. Moreover, they identify upregulation of two microRNAs as potential biomarkers in JMML mononuclear cells, and this upregulation distinguishes JMML caused by PTPN11 mutations from other genetic forms of this disease. © 2015 The Authors. Source

Caye A.,French Institute of Health and Medical Research | Caye A.,University Paris Diderot | Strullu M.,French Institute of Health and Medical Research | Guidez F.,French Institute of Health and Medical Research | And 36 more authors.
Nature Genetics | Year: 2015

Juvenile myelomonocytic leukemia (JMML) is a rare and severe myelodysplastic and myeloproliferative neoplasm of early childhood initiated by germline or somatic RAS-activating mutations. Genetic profiling and whole-exome sequencing of a large JMML cohort (118 and 30 cases, respectively) uncovered additional genetic abnormalities in 56 cases (47%). Somatic events were rare (0.38 events/Mb/case) and restricted to sporadic (49/78; 63%) or neurofibromatosis type 1 (NF1)-associated (8/8; 100%) JMML cases. Multiple concomitant genetic hits targeting the RAS pathway were identified in 13 of 78 cases (17%), disproving the concept of mutually exclusive RAS pathway mutations and defining new pathways activated in JMML involving phosphoinositide 3-kinase (PI3K) and the mTORC2 complex through RAC2 mutation. Furthermore, this study highlights PRC2 loss (26/78; 33% of sporadic JMML cases) that switches the methylation/acetylation status of lysine 27 of histone H3 in JMML cases with altered RAS and PRC2 pathways. Finally, the association between JMML outcome and mutational profile suggests a dose-dependent effect for RAS pathway activation, distinguishing very aggressive JMML rapidly progressing to acute myeloid leukemia. © 2015 Nature America, Inc. Source

Strullu M.,University Paris Diderot | Caye A.,University Paris Diderot | Lachenaud J.,University Paris Diderot | Cassinat B.,University Paris Diderot | And 20 more authors.
Journal of Medical Genetics | Year: 2014

Background: Infants with Noonan syndrome (NS) are predisposed to developing juvenile myelomonocytic leukaemia ( JMML) or JMML-like myeloproliferative disorders (MPD). Whereas sporadic JMML is known to be aggressive, JMML occurring in patients with NS is often considered as benign and transitory. However, little information is available regarding the occurrence and characteristics of JMML in NS. Methods and results: Within a large prospective cohort of 641 patients with a germline PTPN11 mutation, we identified MPD features in 36 (5.6%) patients, including 20 patients (3%) who fully met the consensus diagnostic criteria for JMML. Sixty percent of the latter (12/20) had severe neonatal manifestations, and 10/20 died in the first month of life. Almost all (11/ 12) patients with severe neonatal JMML were males. Two females who survived MPD/JMML subsequently developed another malignancy during childhood. Although the risk of developing MPD/JMML could not be fully predicted by the underlying PTPN11 mutation, some germline PTPN11 mutations were preferentially associated with myeloproliferation: 10/48 patients with NS (20.8%) with a mutation in codon Asp61 developed MPD/JMML in infancy. Patients with a p.Thr73Ile mutation also had more chances of developing MPD/ JMML but with a milder clinical course. SNP array and whole exome sequencing in paired tumoral and constitutional samples identified no second acquired somatic mutation to explain the occurrence of myeloproliferation. Conclusions: JMML represents the first cause of death in PTPN11-associated NS. Few patients have been reported so far, suggesting that JMML may sometimes be overlooked due to early death, comorbidities or lack of confirmatory tests. Source

Cave H.,University Paris Diderot | Caye A.,University Paris Diderot | Strullu M.,University Paris Diderot | Aladjidi N.,Hopital Pellegrin | And 13 more authors.
European Journal of Medical Genetics | Year: 2016

Noonan syndrome is associated with a range of malignancies including acute lymphoblastic leukemia (ALL). However, little information is available regarding the frequency, natural history, characteristics and prognosis of ALL in Noonan syndrome or RASopathies in general. Cross-referencing data from a large prospective cohort of 1176 patients having a molecularly confirmed RASopathy with data from the French childhood cancer registry allowed us to identify ALL in 6 (0.5%) patients including 4/778 (0.5%) with a germline PTPN11 mutation and 2/94 (2.1%) with a germline SOS1 mutation. None of the patients of our series with CFC syndrome (with germline BRAF or MAP2K1/MAP2K2 mutation - n = 121) or Costello syndrome (with HRAS mutation - n = 35) had an ALL. A total of 19 Noonan-ALL were gathered by adding our patients to those of the International Berlin-Munster-Frankfurt (I-BFM) study group and previously reported patients. Strikingly, all Noonan-associated ALL were B-cell precursor ALL, and high hyperdiploidy with more than 50 chromosomes was found in the leukemia cells of 13/17 (76%) patients with available genetics data. Our data suggest that children with Noonan syndrome are at higher risk to develop ALL. Like what is observed for somatic PTPN11 mutations, NS is preferentially associated with the development of hyperdiploid ALL that will usually respond well to chemotherapy. However, Noonan syndrome patients seem to have a propensity to develop post therapy myelodysplasia that can eventually be fatal. Hence, one should be particularly cautious when treating these patients. © 2016 Elsevier Masson SAS. Source

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