title: Spontaneous improvement of hematologic abnormalities in patients having juvenile myelomonocytic leukemia with specific RAS mutations.
abstract: Of 11 children with juvenile myelomonocytic leukemia (JMML) carrying RAS mutations (8 with NRAS mutations, 3 with KRAS2 mutations), 5 had a profound elevation in either or both the white blood cells and spleen size at diagnosis. Three patients had no or modest hepatosplenomegaly and mild leukocytosis at presentation but subsequently showed a marked increase in spleen size with or without hematologic exacerbation, for which nonintensive chemotherapy was initiated. The other three patients with NRAS or KRAS2 glycine to serine substitution received no chemotherapy, but hematologic improvement has been observed during a 2- to 4-year follow up. In the third group, all hematopoietic cell lineages analyzed had the RAS mutations at the time of hematologic improvement, whereas DNA obtained from the nails had the wild type. Additionally, numbers of circulating granulocyte-macrophage progenitors were significantly reduced during the clinical course. Thus, some patients with JMML with specific RAS mutations may have spontaneously improving disease.
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Matsuda
authors.forename: Akira
authors.initials: A
authors.lastname: Shimada
authors.forename: Nao
authors.initials: N
authors.lastname: Yoshida
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ogawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Watanabe
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yajima
authors.forename: Susumu
authors.initials: S
authors.lastname: Iizuka
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Koike
authors.forename: Fumio
authors.initials: F
authors.lastname: Yanai
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Kawasaki
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Yanagimachi
authors.forename: Akira
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Ohtsuka
authors.forename: Eiko
authors.initials: E
authors.lastname: Hidaka
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Miyuki
authors.initials: M
authors.lastname: Tanaka
authors.forename: Ryu
authors.initials: R
authors.lastname: Yanagisawa
authors.forename: Yozo
authors.initials: Y
authors.lastname: Nakazawa
authors.forename: Masaaki
authors.initials: M
authors.lastname: Shiohara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Manabe
authors.forename: Seiji
authors.initials: S
authors.lastname: Kojima
authors.forename: Kenichi
authors.initials: K
authors.lastname: Koike
mesh_terms: D019943:Amino Acid Substitution; D001773:Blood Cells / Q000473:pathology*; D005260:Female; D042381:Granulocyte Precursor Cells; D006801:Humans; D007223:Infant; D015477:Leukemia, Myelomonocytic, Chronic / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D009154:Mutation / Q000502:physiology*; D009365:Neoplasm Regression, Spontaneous / Q000235:genetics*; D018631:ras Proteins / Q000235:genetics* / Q000502:physiology
chemical_list: D018631:ras Proteins