title: Clinical characteristics of 15 children with juvenile myelomonocytic leukaemia who developed blast crisis: MDS Committee of Japanese Society of Paediatric Haematology/Oncology.
abstract: Juvenile myelomonocytic leukaemia (JMML) is a rare haematopoietic stem cell disease of early childhood, which can progress to blast crisis in some children. A total of 153 children diagnosed with JMML were reported to the Myelodysplastic Syndrome Committee in Japan between 1989 and 2007; 15 of them (9·8%) had 20% or more blasts in the bone marrow (blast crisis) during the disease course. Blast crisis occurred during observation without therapy (n = 3) or with oral 6-mercaptopurine treatment (n = 9) and in relapse after haematopoietic stem cell transplantation (HSCT; n = 3). Six patients had a complex karyotype (5 including monosomy 7) and an additional three patients had isolated monosomy 7 at blast crisis. Seven patients received HSCT after blast crisis and four of them achieved remission. Eleven out of the 15 patients died; the cause of death was disease progression in 10 patients and transplant-related complication in one patient. In summary, patients with blast crisis have poor prognosis and can be cured only by HSCT. The emergence of monosomy 7 and complex karyotype may be characteristic of blast crisis in a substantial subset of children.
authors.affiliation: Department of Paediatrics, University of Occupational and Environmental Health, Kitakyusyu, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Honda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tsuchida
authors.forename: Yuji
authors.initials: Y
authors.lastname: Zaike
authors.forename: Atsuko
authors.initials: A
authors.lastname: Masunaga
authors.forename: Ayami
authors.initials: A
authors.lastname: Yoshimi
authors.forename: Seiji
authors.initials: S
authors.lastname: Kojima
authors.forename: Masafumi
authors.initials: M
authors.lastname: Ito
authors.forename: Akira
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Tatsutoshi
authors.initials: T
authors.lastname: Nakahata
authors.forename: Atsushi
authors.initials: A
authors.lastname: Manabe
mesh_terms: D001752:Blast Crisis / Q000235:genetics / Q000628:therapy*; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D002897:Chromosomes, Human, Pair 7; D018450:Disease Progression; D005260:Female; D020022:Genetic Predisposition to Disease; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007223:Infant; D059785:Karyotype; D054429:Leukemia, Myelomonocytic, Juvenile / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
keywords: blast crisis; haematopoietic stem cell transplantation; juvenile myelomonocytic leukaemia; monosomy 7